Minimum Operations to Reduce X to Zero - LeetCode javascript solutions

Problem

You are given an integer array nums and an integer x. In one operation, you can either remove the leftmost or the rightmost element from the array nums and subtract its value from x. Note that this modifies the array for future operations.

Return **the *minimum number* of operations to reduce **x **to *exactly 0 *if it is possible, otherwise, return **-1.

Example 1:

Input: nums = [1,1,4,2,3], x = 5
Output: 2
Explanation: The optimal solution is to remove the last two elements to reduce x to zero.

Example 2:

Input: nums = [5,6,7,8,9], x = 4
Output: -1

Example 3:

Input: nums = [3,2,20,1,1,3], x = 10
Output: 5
Explanation: The optimal solution is to remove the last three elements and the first two elements (5 operations in total) to reduce x to zero.

Constraints:

1 <= nums.length <= 105
1 <= nums[i] <= 104
1 <= x <= 109

Solution

/**
 * @param {number[]} nums
 * @param {number} x
 * @return {number}
 */
var minOperations = function(nums, x) {
    var leftSumMap = { 0: 0 };
    var rightSumMap = { 0: 0 };
    var leftSum = 0;
    var rightSum = 0;
    var min = Number.MAX_SAFE_INTEGER;
    for (var i = 0; i < nums.length; i++) {
      leftSum += nums[i];
      rightSum += nums[nums.length - 1 - i];
      leftSumMap[leftSum] = i + 1;
      rightSumMap[rightSum] = i + 1;
      if (rightSumMap[x - leftSum] !== undefined && (i + 1 + rightSumMap[x - leftSum]) <= nums.length) {
        min = Math.min(min, i + 1 + rightSumMap[x - leftSum]);
      }
      if (leftSumMap[x - rightSum] !== undefined && (i + 1 + leftSumMap[x - rightSum]) <= nums.length) {
        min = Math.min(min, i + 1 + leftSumMap[x - rightSum]);
      }
    }
    return min === Number.MAX_SAFE_INTEGER ? -1 : min;
};

Explain:

nope.

Complexity:

Time complexity : O(n).
Space complexity : O(n * n).