In this page I have listed all the coding questions that have been solved in this website.

Question 3: Count the number of ways a baby can reach the nth stair taking 1 or 2 steps at a time in C language.

Question 4: Sort an array of 0s, 1s and 2s in C

Question 5: Given an array, the difference between the elements is one, find if the “key” element is present or not.

Question 6: Given an unsorted array, find the minimum difference between 2 elements.

Question 7: Given an unsorted array, find the least difference between the element pairs. Display all the pairs present.

Question 9: Given an unsorted integer array, find the smallest missing positive integer.

Question 10: Given an array, find all the repeated elements in C language

Question 11: Given an integer value, convert it into roman number.

Question 12: Given a string, and number of rows, write the string in zigzag pattern.

Question 13: Given a string find the longest Palindromic Substring with detailed explanation and solution in C++.

Question 14: Given an input string (s) and a pattern (p), implement regular expression matching with support for ‘.’ and ‘*’.

Question 15: Find the Container with Most Water explanation with diagram and solution in cpp language

Question 17: Given an array, find 3 elements such that [a + b + c] = 0. Find all the 3 unique elements.

Question 20: Given a linked list Remove Nth Node From End of List

Question 21: Letter Combinations of a Phone Number, solution in C++

Question 22: You are given with n pairs of parentheses, generate all combinations of well-formed parentheses.

Question 23: Merge two sorted linked lists and return it as a new list in C

Question 24: Given linked list swap Nodes in Pairs, solution in C++

Question 25: Divide two integers without using multiplication, division and mod operator

Question 26: Implement next permutation, which rearranges numbers into the next greater permutation of numbers.

Question 28: Merge k sorted linked lists and return it as one sorted list in C++

Question 30: Given a collection of distinct integers, return all possible permutations C++ solution

Question 32: Given a collection of numbers that might contain duplicates, return all possible unique permutations in C++

Question 33: Given an n x n 2D matrix rotate it by 90 degrees (clockwise) in C++ in place

Question 34: Group Anagrams when given an array of strings in C++

Question 35: Rain water trapping in C++

Question 36: Implement pow(x, n), which calculates x raised to the power n (x^n) in C++

Question 37: Given a matrix of m x n elements , print all elements of the matrix in spiral order in CPP

Question 38: Given an array of non-negative integers determine if you are able to reach the last index in C++

Question 39: Merge overlapping Intervals solution in C++

Question 40: Reverse Linked List iterative and recursive in C++

Question 41: Given a positive integer n, generate a square matrix filled with elements from 1 to n^2 in spiral order in C++

Question 42: Wildcard Matching in C++

Question 43: Find Intersection of Two Linked Lists in c++

Question 44: Rotate linked list by k nodes in C++

Question 45: Find path from top right to bottom left with Solution in C++

Question 46: Find path from top right to bottom left with obstacles in C++

Question 47: Minimum Cost Path in CPP

Question 48: Given an absolute path for a file (linux-style), simplify it CPP

Question 49: Reach the end of the array with minimum jumps. Solution in C++

Question 50: Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in-place in CPP

Question 51: Given a 2D Matrix and a key element, search and return if element is present or not in C++

Question 53: Given two integers n and k, return all possible combinations of k numbers out of 1 … n in CPP

Question 54: Given a set of distinct integers, nums, return all possible subsets in CPP

Question 55: Given 2D matrix and a word, find if the word exists in the grid in C++

Question 56: N-Queens in CPP

Question 57: Given a sorted array, remove duplicate elements in-place in CPP

Question 61: You are given a positive number “n”, print the sequence of grey code solution in CPP

Question 62: Given array of integers that might contain duplicates, return all the subsets. Solution in CPP

Question 63: Check if a given string is a valid number in CPP

Question 64: you are given a string having digits, convert into the string by looking at the table given below, solution in C++

Question 65: Reverse Linked List given 2 points m and n, solution in CPP

Question 66: Given a string of integers, restore all valid IP addresses solution in C++

Question 67: Given an array of non overlapping integers, insert a new interval by merging them, solution in C++

Question 68: Given a positive integer, generate pascal triangle, solution in C++

Question 69: Given a positive number “k” return the row of that index of pascals triangle, solution in C++

Question 70: Check if the given board is valid Sudoku or not, explanation with solution in C++

Question 71: Find minimum path from top to bottom in a triangle solution with explanation in C++

Question 72: Optimum Time to Buy and Sell Stock for maximum profit explanation with solution in C++

Question 73: Word Ladder explanation with solution in CPP

Question 74: Given a non-empty array, all the elements appears twice except for one, find that element.

Question 75: Given a string return all the substring that is a palindrome, solution in CPP

Question 76: Given a 2D board with X and O, get all the region surrounded by X, explanation in CPP

Question 77: Check if there is a gas stations along a circular route, solution with explanation in CPP

Question 78: Solve Sudoku, explanation in CPP

Question 79: Given an array every element appears three times except for one. Find that single one. Solution in C++

Question 82: Given a linked list, check if it has a cycle in it, solution in C++

Question 83: Given a linked list, if it has a cycle, get the node where the cycle begins else return NULL.

Question 85: Reorder list in to alternate nodes like first lowest and first highest. Solution in C++

Question 86: Given a linked list, sort the list using insertion sort. Solution with explanation

Question 87: Create a data structure for n elements and constant operations

Question 88: Given an array and a number n, rotate the array by n steps to its right solution in C++

Question 89: Given a string, reverse all the vowels in the string , solution in C++

Question 90: Given an array, check if it has any duplicate elements, 2 solutions in CPP

Question 91: Given a sorted array, find the starting and ending index that matches the target – 2 solutions using C++

Question 93: Given an array, find the continuous sub array that has the largest sum, return the sum. 2 solutions in C++

Question 94: 1’s and 2’s complement of a Binary Number

Question 95: Add and subtract 2 numbers using bitwise operators. C++ Solution

Question 96: Calculate the square of a number and also check if that number is even or odd using bitwise operator.

Question 99: Perform below operations using Bitwise Operators

Question 100: Perform below swapping operations using Bitwise operators

Question 101: Perform multiplication operation using Bitwise operators

Question 102: Perform binary search on a singly linked list, solution in C++

Question 103: Perform bubble sort on singly linked list, solution in C++

Question 104: Perform below operations on Circular Singly Linked List, solution in C++

Question 105: Perform below delete operations from single linked list, solution in C++

Question 106: Perform below delete operations from single linked list, solution in C++

Question 107: Given an unsorted linked list, sort the list using merge sort, solution in C++

Question 108: Given an expression in reverse polish notation, evaluate it and get the output in C++

Question 109: You are given a sentence, reverse the string word by word in C++

Question 110: Given an integer array, find the maximum product made from continuous elements in that array. Solution in C++

Question 111: Find the minimum element from an array that is sorted and is rotated, solution in C++

Question 112: Given an array, find the majority element, solution in C++

Question 113: Given 2 strings, check if they are isomorphic strings, solution in C++

Question 115: Dynamic Programming: Longest Increasing Subsequence

Question 116: Dynamic Programming: Longest Bitonic Subsequence

Question 117: Dynamic Programming: Get Max Coin In Game problem.

Question 118: Dynamic Programming: Rod Cutting Problem

Question 119: Dynamic Programming: Box Stacking Problem

Question 120: Dynamic Programming: Building Bridges

Question 121: Dynamic Programming: Egg Dropping Problem

Question 122: Dynamic Programming: Min Edit Distance

Question 123: Bottom view of binary Tree

Question 124: Boundary Traversal of Binary Tree

Question 125: Top view of a binary tree

Question 126: Left view and right view of a Binary Tree

Question 127: Level Order Traversal

Question 128: Vertical Order Traversal

Question 129: Height or Max depth of a BTree

Question 130: Spiral order or Zigzag traversal of a Binary Tree

Question 131: Diameter of a Binary Tree

Question 132: Lowest Common ancestor of a Binary Tree.

Question 133: Check if 2 nodes are mirror of each other

Question 134: Check if two binary tree are identical

Question 135: Check if binary tree is a sum tree

Question 136: Add all the node values in a Binary Tree or Sum of a Binary tree

Question 137: Print the number of leaf nodes in a binary tree

Question 138: Print all the paths from root node to leaf node

Question 139: Print the nodes at k distance from the root of a binary tree

Question 140: Reverse Bits

Question 141: Count the number of set bits

Question 142: Power of 2

Question 143: Missing Number

Question 144: Counting set bits in a number

Question 145: Hamming Distance

Question 146: Bitwise and of number range

Question 147: Binary search on an array that is in descending order

Question 148: Order-Agnostic Binary Search

Question 149: Find the first and last occurrence of an element

Question 150: Find the number of times a Sorted array is Rotated

Question 151: Searching in a Nearly Sorted Array

Question 152: Find Floor of an element in a Sorted Array

Question 153: Find Ceil of an element in a Sorted Array

Question 154: Find position of an element in an Infinite Sorted Array

Question 155: Find the index of first 1 in an infinite sorted array of 0s and 1s

Question 156: Peak Element

Question 157: Find maximum element in Bitonic Array

Question 158: Search An Element in Bitonic Array

Question 159: Get the rotation count in sorted rotated array

Question 160: Count the number of 1’s in an array sorted in decreasing order.

Question 161: Binary Tree: Get difference between values at Even and Odd level in a binary tree

Question 162: Binary Tree: Get Number of Nodes in a Binary Tree

Question 163: Binary Tree: Display nodes at given level in Binary Tree

Question 164: Binary Tree: Display Reverse Level Order Traversal by using queue

Question 165: Binary Tree: Perform PreOrder traversal on a Binary Tree by without Recursion

Question 166: Binary Tree: Perform InOrder traversal on a Binary Tree by without Recursion

Question 167: Binary Tree: Perform PostOrder traversal on a Binary Tree by without Recursion

Question 168: Binary Tree: Convert a binary tree to its Mirror Tree

Question 169: Binary Tree: Delete a binary tree

Question 170: Binary Tree: Get Level of a Given Node

Question 171: Binary Tree: Get Sum of elements Level wise in a Binary Tree

Question 172: Binary Tree: Get Maximum width of Binary Tree

Question 173: Binary Tree: Display elements between any two given level

Question 174: Binary Tree: Check if binary tree is a height balanced tree?

Question 175: Binary Tree: Check if all Leaf Nodes are at same level in Binary tree

Question 176: Binary Tree: Find Parent of a given node value in Binary Tree

Question 177: Binary Tree: Check if given Binary Tree is BST

Question 178: Binary Tree: Find Sibling node of a given node value in Binary Tree

Question 179: Binary Tree: Check if given two nodes are siblings to each other in Binary Tree

Question 180: Binary Tree: Get Sum of all nodes formed from Root to Leaf Path

Question 181: Binary Tree: Get Average of all nodes in Binary Tree

Question 182: Binary Tree: Get Sum of all Leaf Nodes in Binary Tree

Question 183: Binary Tree: Find Maximum or Minimum in Binary Tree

Question 184: Binary Tree: Check if Binary Tree is Foldable Tree

Question 185: Binary Tree: Check if two Binary Trees are Isomorphic

Question 186: Binary Tree: Get Vertical Sum of Binary Tree

Question 187: Binary Tree: Get deepest Left Leaf Node in Binary Tree

Question 188: Binary Tree: Get depth of Odd level which contains Leaf node in Binary Tree

Question 189: Binary Tree: Display all the leaf nodes from left to right and right to left in a tree

Question 190: Binary Tree: Get count Non-Leaf nodes in a Binary Tree

Question 191: Binary Tree: Get the count full nodes in a Binary

Question 192: Binary Tree: Check if Two Trees are Mirror Structure to each other

Question 193: Arrays: Find numbers with even number of digits

Question 194: Arrays: Find unique numbers that sum upto zero

Question 195: Arrays: Find the k’th smallest/largest element in an array

Question 196: Arrays: Check If N and Its Double Exist

Question 197: Arrays: Move all the negative number in beginning

Question 198: Arrays: Find the union and intersection of two sorted arrays

Question 199: Arrays: Given an array, rotate it one time

Question 200: Arrays: Minimize the maximum difference between the heights

Question 201: Arrays: Given an array find the duplicate number

Question 202: Arrays: Merge Two Sorted arrays without using extra space

Question 203: Arrays: Inversion Count in an Array

Question 204: Arrays: Find common element in 3 sorted arrays.

Question 205: Arrays: Rearrange the array with one positive and one negative number.

Question 206: Arrays: Check if 3 consecutive odds exist

Question 207: Arrays: Merge sorted array inplace

Question 208: Arrays: Find whether an array is subset of another array

Question 209: Arrays: Find a triplet that sum to a given value

Question 210: Arrays: Find triplet with minimum sum

Question 211: Arrays: Three way partitioning of an array around a given range

Question 212: Arrays: Minimum swaps required to bring all elements less than or equal to k together

Question 213: Arrays: Get minimum number of merge operations to make an array palindrome

Question 214: Arrays: Find the median of 2 sorted arrays of same size

Question 215: Arrays: Program to check if an Array is Palindrome or not

Question 216: Matrix: Find median in a row wise sorted matrix.

Question 217: Matrix: Find a row with maximum number of 1’s in a binary matrix

Question 218: Matrix: Get the common elements in all row of a matrix.

Question 219: Strings: Reverse a string

Question 220: Strings: Remove all consecutive duplicates from the string

Question 221: Strings: Print all the duplicates in a string

Question 222: Strings: Given a string convert into its equivalent ASCII form

Question 223: Strings: Program to check if strings are rotations of each other or not

Question 224: Strings: Second most repeated word in a sequence

Question 225: Strings: Longer Contiguous Segments of Ones than Zeros

Question 226: Strings: Given a string, print all the subsequence

Question 227: Strings: Permutations of a given string

Question 228: Strings: Divide binary string into sub strings with equal number of 0s and 1s.

Question 229: Strings: Check balanced parenthesis

Question 230: Strings: Convert a string into its mobile numeric keypad

Question 231: Strings: Get the minimum number of inversions needed to make an expression balanced

Question 232: Strings: Count the number of string in 2D character array

Question 233: Strings: Convert Roman Numerals to Decimal

Question 234: Strings: Longest Common Prefix

Question 235: Strings: Minimum number of flips to make binary string alternate

Question 236: Strings: Minimum swaps required for bracket balancing

Question 237: Strings: Find the first repeated word in a string

Question 238: Strings: Find the longest common subsequence between two strings.

Question 239: Strings: Smallest distinct window

Question 240: Strings: Recursively print all sentences that can be formed from list of word lists

Question 241: Searching and Sorting: Get the fixed point in an array

Question 242: Searching and Sorting: Maximum and minimum of an array using minimum number of comparisons

Question 243: Searching and Sorting: Find the majority element in the array

Question 244: Searching and Sorting: Search an array where adjacent differ by at most k

Question 245: Searching and Sorting: Count all distinct pairs with difference equal to k

Question 246: Searching and Sorting: Maximum sum such that no two elements are adjacent

Question 247: Searching and Sorting: Merge 2 sorted arrays

Question 248: Searching and Sorting: print all subarrays with 0 sum

Question 249: Searching and Sorting: Product of array except itself

Question 250: Searching and Sorting: Sort Integers by The Number of 1 Bits

Question 251: Searching and Sorting: Minimum number of swaps required to sort an array

Question 252: Searching and Sorting: Find the smallest and second smallest elements in an array

Question 253: Searching and Sorting: K-th Element of Two Sorted Arrays

Question 254: Searching and Sorting: Factorial Trailing Zeroes

Question 255: Searching and Sorting: Find the missing number in Arithmetic Progression

Question 256: Linked List: Reverse Linked List in groups

Question 257: Linked List: Remove duplicates from an unsorted linked list

Question 258: Linked List: Move last element to front of a given Linked List

Question 259: Linked List: Add 1 to the linked list

Question 260: Linked List: Find middle element in Linked List

Question 261: Linked List: Split circular Linked List into two halves

Question 262: Linked List: Program to Check if a Singly Linked List is Palindrome

Question 263: Linked List: Deletion from a Circular Linked List

Question 264: Linked List: Reverse a Doubly Linked List

Question 265: Linked List: Find pairs with a given sum in a DLL.

Question 266: Linked List: Count triplets in a sorted DLL whose sum is equal to given value “k”.

Question 267: Linked List: Sort a “k”sorted Doubly Linked list

Question 268: Linked List: Rotate Doubly linked list by N nodes

Question 269: Linked List: Rotate a Doubly Linked list in group of Given Size

Question 270: Linked List: Flatten a Linked List

Question 271: Linked List: Multiply two numbers represented by Linked Lists

Question 272: Linked List: Delete nodes which have a greater value on right side using recursion

Question 273: Linked List: Segregate even and odd nodes in a Linked List

Question 274: Linked List: Odd Even Linked List

Question 275: Binary Trees: Diagonal Traversal of a Binary tree

Question 276: Binary Trees: Convert Binary tree into Sum tree

Question 277: Binary Trees: Construct Binary Tree from preorder and inorder traversal

Question 278: Binary Trees: Minimum swap required to convert binary tree to binary search tree

Question 279: Binary Trees: Convert Binary Tree to DLL

Question 280: Binary Trees: Find Duplicate Subtrees

Question 281: Binary Trees: Find largest subtree sum in a tree

Question 282: Binary Search Trees: Find a value in a BST

Question 283: Binary Search Trees: Deletion of a node in a BST

Question 284: Binary Search Trees: Find min and max value in a BST

Question 285: Binary Search Trees: Find the Inorder predecessor and successor for a given key in BST

Question 286: Binary Search Trees: A program to check if a binary tree is BST or not

Question 287: Binary Search Trees: Convert a BST into greater sum tree

Question 288: Binary Search Trees: LCA in a BST

Question 289: Binary Search Trees: Construct BST from preorder traversal

Question 290: Binary Search Trees: Convert Binary Tree into Binary Search Tree.

Question 291: Binary Search Trees: Convert a normal BST into a Balanced BST

Question 292: Binary Search Trees: Merge Two balanced BST

Question 293: Binary Search Trees: Kth Largest Element in a BST

Question 294: Binary Search Trees: Kth smallest Element in a BST

Question 295: Binary Search Trees: Return the sum of given range in BST.

Question 296: Binary Search Trees: Get the Shortest distance between two nodes in BST

Question 297: Binary Search Trees: Count the number of BST nodes that lie in a given range.

Question 298: Binary Search Trees: Convert sorted DLL to Balanced BST

Question 299: Binary Search Trees: Find triplet sum in BST

Question 300: Binary Search Trees: Check if the pre-order is a valid BST

Question 301: Binary Search Trees: Check if the BST has a dead end

Question 302: Binary Search Trees: Correct a BST where 2 nodes are swapped

Question 303: Binary Search Trees: Flatten BST to sorted list

Question 304: Greedy: Remove duplicates from a string

Question 305: Greedy: Add elements in an array so the sum is equal to the given range

Question 306: Greedy: Remove k digits from an number to make it a smallest integer.

Question 307: Greedy: Get the minimum platforms needed to avoid delay in the train arrival.

Question 308: Greedy: Check if the string is a substring of another string

Question 309: Greedy: Remove overlapping intervals.

Question 310: Greedy: Plant n flowers in flower bed

Question 311: Greedy: Maximum meetings in one room

Question 312: Greedy: Distribute Candy

Question 313: Greedy: Shuffle array so that one array element is greater than other array element

Question 314: Greedy: Schedule task efficiently

Question 315: Greedy: Maximum sum of absolute difference of an array

Question 316: Greedy: Maximum sum of absolute difference of an array

Question 317: Greedy: Juice change

Question 318: Greedy: Given a string, split into balanced strings.

Question 319: Greedy: Perform operations on a broker calculator

Question 320: Greedy: Add minimum to make parentheses valid.

Question 321: Greedy: Remove covered intervals.

Question 322: Greedy: Reduce the array size to the half

Question 323: Greedy: String break problem

Question 324: Greedy: Connect ropes with minimum cost.

Question 325: Greedy: Find maximum sum possible equal sum of three stacks

Question 326: Backtracking: Partition string into its palindrome

Question 327: Backtracking: You are given an array with repeated elements and a key element, find all unique combination to the key

Question 328: Backtracking: Get the k combination from an array of 1 to n

Question 329: Backtracking: Find combination sum of k numbers that sum up to n

Question 330: Backtracking: Letter case permutation

Question 331: Backtracking: Return the number of queens possible in a chessboard

Question 332: Backtracking: Get the sequential digits from the given range

Question 333: Backtracking: Partition to K Equal Sum Subsets

Question 334: Matrix: Find pair with maximum sum in the matrix.

Question 335: Matrix: Kth smallest element in a sorted matrix

Question 336: Strings: Minimum Number of Swaps to Make the Binary String Alternating

Question 337: Strings: Longest Substring Of All Vowels in Order

Question 338: Strings: Word Break Problem

Question 339: Strings: Check if it is possible to re-arrange characters in a string, such a way that no two adjacent are same

Question 340: Strings: Check if Word Equals Summation of Two Words

Question 341: Strings: Minimum Window Substring

Question 342: Strings: Remove all consecutive duplicates from the string

Question 343: Strings: Longest Prefix Suffix

Question 344: Strings: Find minimum operations required to transform a string into another string

Question 345: Strings: Number of Different Integers in a String

Question 346: Binary Trees: Check if a given graph is tree or not

Question 347: Binary Trees: Maximum Sum of nodes in Binary tree such that no two are adjacent

Question 348: Binary Trees: Kth Ancestor of a Tree Node

Question 349: Binary Trees: Find Duplicate Subtrees

Question 350: Backtracking: Get maximum sum in a matrix

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