升序排列数组

  1. function merge(left, right) {
  2.   const res = [];
  4.   while (left.length && right.length) {
  5.     left[0] <= right[0] ? res.push(left.shift()) : res.push(right.shift());
  6.   }
  8.   return res.concat(left, right);
  9. }
  11. function mergeSort(arr) {
  12.   if (arr.length < 2) {
  13.     return arr;
  14.   }
  16.   const mid = Math.floor(arr.length / 2);
  17.   const left = arr.slice(0, mid);
  18.   const right = arr.slice(mid);
  20.   return merge(mergeSort(left), mergeSort(right));
  21. }

算法测试

  1. console.log(mergeSort([5, 4, 6, 3, 35, 17, 1]));
  2. // [ 1,  3,  4, 5, 6, 17, 35 ]
  4. console.log(mergeSort([12, 1, 5, 5, 7, 78]));
  5. // [ 1, 5, 5, 7, 12, 78 ]
  7. console.log(mergeSort([-3, 7, -8, 4, 6, -5, -4, 5]));
  8. // [ -8, -5, -4, -3, 4,  5,  6,  7 ]