合并两个有序数组，放在A中，A中的空间足够。
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.
从后往前放，比较A和B的从后往前的，比较大的放在m+n-1的位置。然后一直减减。
class Solution { public: void merge(int A[], int m, int B[], int n) {while(m > 0 && n > 0) { if (A[m-1] > B[n-1]) { A[m+n-1] = A[m-1]; m--; } else { A[m+n-1] = B[n-1]; n--; } } if (m == 0) while(n > 0) { A[n-1] = B[n-1]; n--; } return ; } };
也可以写短一点：
class Solution { public: void merge(int A[], int m, int B[], int n) { int nowA = m - 1, nowB = n - 1, last = n + m - 1; while(nowA >= 0 && nowB >=0) { A[last--] = A[nowA] > B[nowB] ? A[nowA--] : B[nowB--]; } while(nowB >= 0) A[last--] = B[nowB--]; return ; } };
leetcode[89] Merge Sorted Array
原文：http://www.cnblogs.com/higerzhang/p/4114568.html