Minimum Operations to Reduce X to Zero.java

// 1658. Minimum Operations to Reduce X to Zero (https://leetcode.com/problems/minimum-operations-to-reduce-x-to-zero)

// 슬라이딩 윈도우 알고리즘
class Solution {
    public int minOperations(int[] nums, int x) {
        int sum = 0;
        for (int num : nums) 
            sum += num;
        
        int maxLen = -1, curSum = 0;
        for (int l = 0, r = 0; r < nums.length; r++) {
            curSum += nums[r];
            while (l <= r && curSum > sum - x) 
                curSum -= nums[l++];
            if(curSum == sum - x) maxLen = Math.max(maxLen, r-l + 1);
        }

        return maxLen == -1 ? -1 : nums.length - maxLen;
    }
}