leetcode88. Merge Sorted Array

88. Merge Sorted Array

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.

Note:
You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2. The number of elements initialized in nums1 and nums2 are m and n respectively.

解法

归并排序。从后往前排。

public class Solution {    public void merge(int[] nums1, int m, int[] nums2, int n) {        if (nums1 == null || nums1.length == 0) {            return;        }        if (nums2 == null || nums2.length == 0) {            return;        }        int i = m - 1, j = n - 1, k = n + m - 1;        while (i >= 0 && j >= 0) {            if (nums1[i] >= nums2[j]) {                nums1[k--] = nums1[i--];            } else {                nums1[k--] = nums2[j--];            }        }        // 其实本步不太需要，因为剩下的元素都存在nums1中        while (k >= 0 && i >= 0) {            nums1[k--] = nums1[i--];        }        while (k >= 0 && j >= 0) {            nums1[k--] = nums2[j--];        }    }}