[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 and n respectively.

这道题思路很简单，但是要记得考虑corner case.

基本思路是，在m, n 均大于0的时候，从后往前扫描两个数组并逐一比较，把大的放到A的最后面。

corner case是当m = 0时，直接把B的元素全部直接复制进A

当 n = 0 时，不用处理

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--;
}
}
while (n > 0) {
A[m + n - 1] = B[n - 1];
n--;
}