Binary Search

Medium Recursion

Solve in Playground →

Problem Statement

Write a C++ recursive function to perform binary search on a sorted array.

Input Format

First line: N and Target. Second line: N sorted integers.

Output Format

Print index of target, or -1 if not found.

Constraints

1 <= N <= 100

Sample Input

5 30
10 20 30 40 50

Sample Output

Explanation

Recursively narrows search boundaries in $O(log N)$ time complexity.

Starter Code

#include <iostream>
#include <vector>

int binarySearch(const std::vector<int>& arr, int low, int high, int target) {
    // Write your code here
}

int main() {
    int n, target;
    if (std::cin >> n >> target) {
        std::vector<int> arr(n);
        for (int i = 0; i < n; i++) std::cin >> arr[i];
        std::cout << binarySearch(arr, 0, n - 1, target) << "n";
    }
    return 0;
}

Limits

Time Limit: 1s
Memory Limit: 256MB

Start Coding in IDE →