15.三数相加/Three Sum

/**
 * @param {number[]} nums
 * @return {number[][]}
 */
var threeSum = function (nums) {
  var result = [];
  nums = nums.sort((a,b) => a - b);
  for (var i = 0; i < nums.length - 2; i++) {
    if (nums[i] !== nums[i - 1]) {
      var start = i + 1;
      var end = nums.length - 1;
      while (start < end) {
        if (nums[i] + nums[start] + nums[end] < 0) {
          start++;
        } else if (nums[i] + nums[start] + nums[end] > 0) {
          end--;
        } else {
          result.push([nums[i], nums[start], nums[end]]);
            do{
                start++;
            }
            while(nums[start] === nums[start - 1])

        }
      }
    }
  }
  return result;
};