0209-minimum-size-subarray-sum.js

/**
 * 209. Minimum Size Subarray Sum
 * https://leetcode.com/problems/minimum-size-subarray-sum/
 * Difficulty: Medium
 *
 * Given an array of positive integers nums and a positive integer target, return the
 * minimal length of a subarray whose sum is greater than or equal to target. If there
 * is no such subarray, return 0 instead.
 */

/**
 * @param {number} target
 * @param {number[]} nums
 * @return {number}
 */
var minSubArrayLen = function(target, nums) {
  let result = Infinity;

  for (let right = 0, sum = 0, left = 0; right < nums.length; right++) {
    sum += nums[right];
    while (sum >= target) {
      result = Math.min(result, right - left + 1);
      sum -= nums[left];
      left++;
    }
  }

  return result === Infinity ? 0 : result;
};

// var minSubArrayLen = function(target, nums) {
//   let begin = 0
//   let window_state = 0
//   let result = Infinity;

//   for (let end = 0; end < nums.length; end++) {
//       window_state += nums[end]

//       while (window_state >= target) {
//           let window_size = end - begin + 1
//           result = Math.min(result, window_size)
//           window_state -= nums[begin]
//           begin++
//       }
//   }

//   if (result === Infinity) return 0
//   return result
// };