《leetCode》：Merge Sorted Array

题目

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.

//思路：从后往前遍历
void merge(int* nums1, int m, int* nums2, int n) {
if(n<1){
return ;
}
if(m<1){//第一个数组元素为空
for(int i=0;i<n;i++){
nums1[i]=nums2[i];
}
return ;
}
int index=m+n-1;
int p1=m-1;
int p2=n-1;
while(p1>=0&&p2>=0){
if(nums1[p1]>=nums2[p2]){
nums1[index--]=nums1[p1];
p1--;
}
else if(nums1[p1]<nums2[p2]){
nums1[index--]=nums2[p2];
p2--;
}
}
//如果是p2<0退出，则就已完成，如果是p1<0退出，则还需要将p2个元素拷贝要nums1中
if(p1<0&&p2>=0){
for(int i=0;i<=p2;i++){
nums1[i]=nums2[i];
}
}

}