Search Insert Position

class Solution {
public:
int searchInsert(vector<int>& nums, int target) {
int left=0;
int right=nums.size()-1;
int mid;

if(nums.size()==0) return 0;

while(left < right){
mid = (left + right)/2;
if(nums[mid] == target) return mid;
else if(nums[mid] < target) left = mid+1;
else right = mid-1;
}
//循环的出口是left = right
if(target <= nums[left]) return left;  //排在当前元素的位置
else   return left+1;   //排在当前元素之后

}
};