Educational Codeforces Round 54 (Rated for Div. 2) C. Meme Problem

二分搜索

推下方程把前半部分去掉

/*
    Zeolim - An AC a day keeps the bug away
*/

//pragma GCC optimize(2)
#include <cstdio>
#include <iostream>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <string>
#include <cstring>
#include <algorithm>
#include <stack>
#include <queue>
#include <set>
#include <sstream>
#include <map>
#include <ctime>
#include <vector>
#include <fstream>
#include <list>
#include <iomanip>
#include <numeric>
using namespace std;
typedef long long ll;

const int MAXN = 1e6 + 10;

const double eps = 1e-6;

int main()
{
    //ios::sync_with_stdio(false);
    //cin.tie(0);     cout.tie(0);
    //freopen("D://test.in", "r", stdin);
    //freopen("D://test.out", "w", stdout);
    
    int n;

    cin>>n;

    while(n--)
    {
        double x;
        
        cin>>x;

        double fst = x / 2, lst = x, mid;

        for(int i = 0; i < 100; i++)
        {
            mid = (fst + lst) / 2;

            if( (x - mid) * mid > x)
                fst = mid;
            else
                lst = mid;
        }
		if( fabs( fst * (x - fst) - x ) <= eps )
        	printf("Y %.9lf %.9lf
", fst, x - fst);
    	else
    		printf("N
");
    }

    return 0;
}