题解 | #三数之和#

/**
 *
 * @param num int整型一维数组
 * @return int整型二维数组
 */
function threeSum(num) {
  // write code here
  const res = [];
  const size = num.length;
  if (size === 0 || size < 3) return res;
  num.sort((a, b) => a - b);
  for (let i = 0; i < size - 2; i++) {
    if (i > 0 && num[i] === num[i - 1]) continue;
    let L = i + 1,
      R = size - 1;

    while (L < R) {
      const sum = num[i] + num[L] + num[R];
      if (sum === 0) {
        res.push([num[i], num[L], num[R]]);
        while (L < R && num[L] === num[L + 1]) {
          L++;
        }
        while (L < R && num[R] === num[R - 1]) {
          R--;
        }
        L++;
        R--;
      } else if (sum < 0) L++;
      else if (sum > 0) R--;
    }
  }
  return res;
}
module.exports = {
  threeSum: threeSum,
};