15 - 三数之和 about leetcode HOT 1 OPEN

function threeSum(nums: number[]): number[][] {
  const result: number[][] = [];
  const len = nums.length;
  if (len < 3) return result;
  nums.sort((a, b) => a - b);
  for (let i = 0; i < len - 2; i++) {
    if (nums[i] > 0) break;
    if (i > 0 && nums[i] === nums[i - 1]) continue;
    let l = i + 1;
    let r = len - 1;
    while (l < r) {
      const sum = nums[i] + nums[l] + nums[r];
      if (sum === 0) {
        result.push([nums[i], nums[l], nums[r]]);
        while (l < r && nums[l] === nums[l + 1]) l++;
        while (l < r && nums[r] === nums[r - 1]) r--;
        l++;
        r--;
      } else if (sum < 0) {
        l++;
      } else {
        r--;
      }
    }
  }
  return result;
}