Star

LeetCode 88.Merged Sorted Array

Posted on | In |

Question

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.

Explanation

重点在于已经是sort好的了，并且不能从头开始比较，那会打乱顺序。从后开始更容易。

Code

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
public class Solution {
    public void merge(int[] nums1, int m, int[] nums2, int n) {
        int index = n+m -1;
        int i = m-1;
        int j = n-1;
        // 从最后开始比较，往nums1中放
        while(i >= 0 && j >= 0) {
            if (nums1[i] > nums2[j]) {
                nums1[index--] = nums1[i--];
            } else {
                nums1[index--] = nums2[j--];
            }
        }
        while(j>=0) nums1[index--] = nums2[j--];
        return;
    }
}