jd 疯狂数列 10行KO

#include<iostream>
#include<cmath>
using namespace std;
int main(int argc,char* argv[]){
     int n;
     cin>>n;
     int tmp = sqrt(2*n);
     int low = tmp* (tmp -1) /2, high = low + tmp; //边界情况
     while(n <= low || n > high){
        if(n > high)  ++tmp;
        else  --tmp;
        low = tmp* (tmp -1) /2;
        high = low + tmp;
     }
     cout<<tmp;
	return 0;
}