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.
剑指offer的经典题，利用指针从后边开始往前一个一个排列数字。
class Solution {
public:
void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) {
if (n == ) return;
if (m == ) {
for (int i = ; i < n; i++){
nums1[i] = nums2[i];
}
return;
}
int p = m + n - , p1 = m - , p2 = n - ;
while (p1 >= && p2 >= ){
int maxval = max(nums1[p1], nums2[p2]);
if (maxval == nums1[p1]){
p1--;
}else{
p2--;
}
nums1[p] = maxval;
p--;
}
while (p2 >= ){
nums1[p--] = nums2[p2--];
}
return;
}
};