How to find the suarray with maximum sum using divide and conquer

Sure! Here is a response without any personal words or sentences at the beginning and end:

Explanation:

To find the subarray with the maximum sum using divide and conquer in C++, we can follow these steps:

  1. Divide: Divide the given array into two equal halves.
  2. Conquer: Recursively find the maximum subarray sum in the left and right halves of the array, and also find the maximum subarray sum crossing the middle element.
  3. Combine: Compare the maximum subarray sums obtained from the left half, right half, and the middle part of the array. The maximum among these three will be the maximum subarray sum of the original array.

Here is the code implementation for finding the subarray with the maximum sum using the divide and conquer approach in C++:

#include <iostream>
#include <climits>

// Function to find the maximum subarray sum crossing the middle element
int maxCrossingSum(int arr[], int low, int mid, int high) {
    int left_sum = INT_MIN;
    int sum = 0;

    for (int i = mid; i >= low; i--) {
        sum += arr[i];
        if (sum > left_sum)
            left_sum = sum;
    }

    int right_sum = INT_MIN;
    sum = 0;

    for (int i = mid + 1; i <= high; i++) {
        sum += arr[i];
        if (sum > right_sum)
            right_sum = sum;
    }

    return left_sum + right_sum;
}

// Function to find the maximum subarray sum using divide and conquer
int maxSubarraySum(int arr[], int low, int high) {
    if (low == high)
        return arr[low];

    int mid = (low + high) / 2;

    int left_sum = maxSubarraySum(arr, low, mid);
    int right_sum = maxSubarraySum(arr, mid + 1, high);
    int crossing_sum = maxCrossingSum(arr, low, mid, high);

    return std::max(std::max(left_sum, right_sum), crossing_sum);
}

// Driver code
int main() {
    int arr[] = { -2, -5, 6, -2, -3, 1, 5, -6 };
    int n = sizeof(arr) / sizeof(arr[0]);

    int max_sum = maxSubarraySum(arr, 0, n - 1);

    std::cout << "Maximum subarray sum is: " << max_sum << std::endl;

    return 0;
}

This code will output the maximum subarray sum of the given array. In the provided example, the input array is {-2, -5, 6, -2, -3, 1, 5, -6}, and the maximum subarray sum is 7, which corresponds to the subarray {6, -2, -3, 1, 5}.