L44 Minimum Subarray

Given an array of integers, find the subarray with smallest sum.

Return the sum of the subarray.

Notice

The subarray should contain one integer at least.

Example

For[1, -1, -2, 1], return-3.

every element multiply -1

then find max subarray sum

then sum * -1

public int minSubArray(ArrayList<Integer> nums) {
    if (nums == null || nums.size() == 0) {
        return 0;
    }

    for (int i = 0; i < nums.size(); i++) {
        nums.set(i, nums.get(i) * -1);
    }

    int sum = 0;
    int max = Integer.MIN_VALUE;
    for (int i = 0; i < nums.size(); i++) {
        sum = sum + nums.get(i);
        if (sum > max) {
            max = sum;
        }

        if (sum < 0) {
            sum = 0;
        }
    }

    return max * -1;
}