首页 > 代码库 > 【leetcode】Merge Sorted Array

【leetcode】Merge Sorted Array

Given two sorted integer arrays A and B, merge B into A as one sorted array.

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


题解:查了资料才想到要从后往前合并。把end初始化为m+n-1,即A在合并后最后一个元素的位置。然后把A和B从后往前比较,较大的元素放在end所指的地方。最后要特别注意B的处理,如果A的元素遍历完了,但是B中的元素还没有全部放到A中去,要再用一个while循环单独处理B。

代码如下:

 1 class Solution {
 2 public:
 3     void merge(int A[], int m, int B[], int n) {
 4         int end = m+n-1;
 5         int i,j;
 6         for(i = m-1,j =n-1;i>=0 && j>=0;){
 7             if(A[i] > B[j]){
 8                 A[end] = A[i];
 9                 i--;
10             }
11             else{
12                 A[end] = B[j];
13                 j--;
14             }
15             end --;
16         }
17 
18        //B中还有元素,继续处理
19         while(j >= 0)
20         {
21             A[end] = B[j];
22             j--;
23             end--;
24         }
25     }
26 };