Assume the structure of a Linked List node is as follows. C++ struct Node { int data; struct Node *next; }; // This code is contributed by SHUBHAMSINGH10 C struct Node { int data; struct Node *next; }; Java static class Node { int data; Node next; }; // This code is contributed by shubhamsingh10…

Question 1 Predict the output of the following program. C++ #include using namespace std; void fun(int x) { if(x > 0) { fun(--x); cout << x <<" "; fun(--x); } } int main() { int a = 4; fun(a); return 0; } // This code is contributed by SHUBHAMSINGH10 C #include void fun(int x) { if(x > 0) {…

Explain the functionality of below recursive functions. Question 1 C++ void fun1(int n) { int i = 0; if (n > 1) fun1(n - 1); for (i = 0; i < n; i++) cout << " * "; } // This code is contributed by shubhamsingh10 C void fun1(int n) { int i = 0; if (n > 1) fun1(n-1); for (i = 0; i < n; i++) printf(" *…

Explain the functionality of the following functions. Question 1 C++ /* Assume that n is greater than or equal to 1 */ int fun1(int n) { if (n == 1) return 0; else return 1 + fun1(n / 2); } Java /* Assume that n is greater than or equal to 1 */ static int fun1(int n) { if (n == 1) return 0; else…

Explain the functionality of the following functions. Question 1 C++ int fun1(int x, int y) { if (x == 0) return y; else return fun1(x - 1, x + y); } C int fun1(int x, int y) { if (x == 0) return y; else return fun1(x - 1, x + y); } Java static int fun1(int x, int y) { if (x == 0) return y; else…

Recursive Practice Problems with Solutions Last Updated : 06 Feb, 2024 Improve Suggest changes Like Article Like Report

Depth-First Search (DFS) is a method used to explore all the nodes in a tree by going as deep as possible along each branch before moving to the next one. It starts at the root node and visits every node in the tree. Depth-First Search (DFS) can be classified into three main types based on the order…

Given a Binary Tree and a node key. The task is to print all the ancestors of the given key in the tree without using recursion. An ancestor of a node is any node that lies on the path from the root to that node, excluding the node itself. Note: All node values are unique, and the given key is…

Try it on GfG Practice Given an integer array arr[] of size n, the task is to find the maximum of the minimums for every window size in the given array, where the window size ranges from 1 to n. Example: Input: arr[] = [10, 20, 30] Output: [30, 20, 10] Explanation: First element in output indicates…

Given a string s of length n, consisting of opening and closing brackets and an array queries[] consisting of q queries of type [start, end], where start defines the starting point and end defines the ending point. For each query, the task is to find the maximum length of the valid bracket…

Try it on GfG Practice Given a histogram represented by an array arr[], where each element of the array denotes the height of the bars in the histogram. All bars have the same width of 1 unit. Task is to find the largest rectangular area possible in a given histogram where the largest rectangle can…

Given an array arr[] of size n, the task is to count the number of unique differences between the two maximum elements of every subarray of size at least 2 of the given array. Examples: Input: arr[] = { 5, 1, 3 }, n = 3 Output: 2 Explanation: The subarrays are {5, 1}, {5, 1, 3}, {1, 3}. {5, 1} -…

Given an array height[] which represents the height of n people standing in a line. A person i can see a person j if height[j] < height[i] and there is no person k standing in between them such that height[k] >= height[i]. Find the maximum number of people a person can see. Note: A person can see…

Try it on GfG Practice Design a stack data structure that supports the following four operations, each in constant time complexity, i.e., O(1): push(x): Insert an element x onto the top of the stack.pop(): Remove and return the element at the top of the stack.findMiddle(): Retrieve the middle…

Given a binary matrix mat[][] of size n * m, your task is find the maximum area of the rectangle binary-sub-matrix with all 1’s. Examples: Input: mat[][] = [ [0, 1, 1, 0], [1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 0, 0] ] Output: 8 Explanation: The rectangle spanning from cell [1, 0] to [2, 3] consists of…

Try it on GfG Practice Given a square matrix mat[][] of size n x n, such that mat[i][j] = 1 means ith person knows jth person, the task is to find the celebrity. A celebrity is a person who is known to all but does not know anyone. Return the index of the celebrity, if there is no celebrity return…

Stack and doubly linked lists are two important data structures with their own benefits. Stack is a data structure that follows the LIFO (Last In First Out) order and can be implemented using arrays or linked list data structures. Doubly linked list has the advantage that it can also traverse the…

Given an array of size n, the task is to implement k stacks using a single array. We mainly need to perform the following type of queries on the stack. push(x, i) : This operations pushes the element x into stack i pop(i) : This operation pops the top of stack i Here i varies from 0 to k-1 Naive…

Given two expressions in the form of strings. The task is to compare them and check if they are similar. Expressions consist of lowercase alphabets, '+', '-' and '( )'. Examples: Input : exp1 = "-(a+b+c)" exp2 = "-a-b-c" Output : Yes Explanation : The first expression, when simplified by…

Design a Data Structure that can support the following operations in O(1) Time Complexity. insert(x): Inserts x in the data structure. Returns True if x was not present and False if it was already present.remove(x): Removes x from the data structure, if present.getRandom(): Returns any value present…

Try it on GfG Practice Design a Data Structure SpecialStack that supports all the stack operations like push(), pop(), peek() and an additional operation getMin() which should return minimum element from the SpecialStack. All these operations of SpecialStack must have a time complexity of O(1).…

Try it on GfG Practice A stack permutation refers to the rearrangement of elements from an input queue to an output queue using a stack, where elements are transferred with the help of stack operations like push and pop. The rules are as follows: Dequeue elements only from the input queue.Utilize…

Given an array arr[1..n], for each element at position i (1 <= i <= n), define the following: left(i) is the closest index j such that j < i and arr[j] > arr[i]. If no such j exists, then left(i) = 0.right(i) is the closest index k such that k > i and arr[k] > arr[i]. If no such k exists, then…

Given an array of integers, the task is to find the maximum absolute difference between the nearest left and the right smaller element of every element in the array. Note: If there is no smaller element on right side or left side of any element then we take zero as the smaller element. For example…

Try it on GfG Practice Given an array, for each element find the value of the nearest element to the right which is having a frequency greater than that of the current element. If there does not exist an answer for a position, then make the value '-1'. Examples: Input: arr[] = [2, 1, 1, 3, 2, 1]…

Try it on GfG Practice Given a string with brackets. If the start index of the open bracket is given, find the index of the closing bracket. Examples: Input : string = [ABC[23]][89] index = 0 Output : 8 The opening bracket at index 0 corresponds to closing bracket at index 8. Recommended Practice…

Given an array arr[] of size N, the task is to find the number of subarrays whose first element is not greater than other elements of the subarray. Examples: Input: arr = {1, 2, 1} Output: 5 Explanation: All subarray are: {1}, {1, 2}, {1, 2, 1}, {2}, {2, 1}, {1}From above subarray the following…

Given a string S consisting of '(', ')', '[' and ']', the task is to find the minimum count of remaining characters in the string by removing subsequences of the valid parenthesis. Examples: Input: S = "[]])([" Output: 4 Explanation: Removing the subsequence { str[0], str[1] } modifies S to "])([".…

Given a Binary Tree, the task is to check if the given binary tree is a Binary Search Tree or not. If found to be true, then print "YES". Otherwise, print "NO". Examples: Input: 9 / \ 6 10 / \ \ 4 7 11 / \ \ 3 5 8 Output: YES Explanation: Since the left subtree of each node of the tree consists of…

Given a string S, the task is to find the lexicographically largest subsequence that can be formed using all distinct characters only once from the given string. Examples: Input: S = ababc Output: bac Explanation:All possible subsequences containing all the characters in S exactly once are {"abc",…

Try it on GfG Practice Given an array of n strings arr[]. The task is to determine the number of words remaining after pairwise destruction. If two consecutive words in the array are identical, they cancel each other out. This process continues until no more eliminations are possible. Examples:…

Try it on GfG Practice Create a data structure twoStacks that represent two stacks. Implementation of twoStacks should use only one array, i.e., both stacks should use the same array for storing elements. Following functions must be supported by twoStacks. push1(int x) --> pushes x to first stack…

Try it on GfG Practice Write a program to reverse a stack using recursion, without using any loop. Example: Input: elements present in stack from top to bottom 4 3 2 1 Output: 1 2 3 4 Input: elements present in stack from top to bottom 1 2 3 Output: 3 2 1 The idea of the solution is to hold all…

Try it on GfG Practice Given a stack of integers, sort it in ascending order using another temporary stack. Examples: Input: [34, 3, 31, 98, 92, 23] Output: [3, 23, 31, 34, 92, 98] Explanation: After Sorting the given array it would be look like as [3, 23, 31, 34, 92, 98] Input: [3, 5, 1, 4, 2, 8]…

Given array of integer, find the next smaller of next greater element of every element in array. Note : Elements for which no greater element exists or no smaller of greater element exist, print -1. Examples: Input : arr[] = {5, 1, 9, 2, 5, 1, 7} Output: 2 2 -1 1 -1 -1 -1 Explanation : Next Greater…

Try it on GfG Practice Given string str, we need to print the reverse of individual words. Examples: Input: Hello World Output: olleH dlroW Explanation: Each word in "Hello World" is reversed individually, preserving the original order, resulting in "olleH dlroW". Input: Geeks for Geeks Output:…

Try it on GfG Practice Given a stack with push(), pop(), and empty() operations, The task is to delete the middle element of it without using any additional data structure. Input: s = [10, 20, 30, 40, 50] Output: [50, 40, 20, 10] Explanation: The bottom-most element will be 10 and the top-most…

Given a stack, the task is to reverse the stack using the queue data structure. Examples: Input: Stack: (Top to Bottom) [10 -> 20 -> 30 -> 40] Output: Stack: (Top to Bottom) [40 -> 30 -> 20 -> 10] Input: Stack: [6 -> 5 -> 4] Output: Stack: [4 -> 5 -> 6] Approach: The problem can be solved based on…

Try it on GfG Practice Given a string s representing an expression containing various types of brackets: {}, (), and [], the task is to determine whether the brackets in the expression are balanced or not. A balanced expression is one where every opening bracket has a corresponding closing bracket…

Try it on GfG Practice Given two strings string1 and string2, remove those characters from the first string(string1) which are present in the second string(string2). Both strings are different and contain only lowercase characters. NOTE: The size of the first string is always greater than the size…