C++ 代码
class Solution {
public:
int getMissingNumber(vector<int>& nums) {
if(nums.empty()) return 0;
int l=0,r=nums.size()-1;
while(l<r){
int mid=(l+r)/2;
if(nums[mid]!=mid) r=mid-1;
else l=mid+1;
}
if(nums[r]==r) r++;
return r;
}
};