Java Interview Question

Finding the Maximum Subarray Sum

2 août 2023 à 13:57:14

Hello,

I recently came across interesting Java interview questions and answers on the Java Interview Questions page.

Problem Statement:

Given an array of integers, our task is to find the maximum sum of any contiguous subarray (a subarray that appears in consecutive positions) of the input array.

Example:

Input: [-2, 1, -3, 4, -1, 2, 1, -5, 4]
Output: 6
Explanation: The subarray [4, -1, 2, 1] has the maximum sum of 6.

I find this problem particularly fascinating and challenging, as it requires an efficient algorithm to find the maximum subarray sum, considering both positive and negative integers.

If any of you have already tackled this problem or have insights into how to approach it effectively in Java, I would love to hear your solutions or thought processes. Sharing your code snippets or pseudocode would be highly appreciated.

DuboisEmma

14 août 2023 à 12:02:24

One way is to use the Kadane’s algorithm which has a time complexity of O(n) and doesn’t require any extra space. The algorithm works by iterating through the array and keeping track of the maximum sum seen so far and the maximum sum ending at the current position.

Here’s an implementation of Kadane’s algorithm in Java:

One way is to use the Kadane’s algorithm which has a time complexity of O(n) and doesn’t require any extra space. The algorithm works by iterating through the array and keeping track of the maximum sum seen so far and the maximum sum ending at the current position1.

Here’s an implementation of Kadane’s algorithm in Java:

public static int maxSubArray(int[] nums) {
    int maxSoFar = nums[0];
    int maxEndingHere = nums[0];
    for (int i = 1; i < nums.length; i++) {
        maxEndingHere = Math.max(maxEndingHere + nums[i], nums[i]);
        maxSoFar = Math.max(maxSoFar, maxEndingHere);
    }
    return maxSoFar;
}

@bloxd io