Submission #1628918

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Source Code Expand

#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define REP(i, n) rep(i, 0, n)
#define repb(i, a, b) for(int i = a; i >= b; i--)
#define all(a) a.begin(), a.end()
#define int long long
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
using namespace std;
typedef pair<int, int> P;
const int mod = 1000000007;
const int INF = 1e12;

int x, p;


bool f(double m){
    double aoki = m;
    double tak = (double)x + m * (1.0 - 2.0 * p / 100.0);
    // cout << m << " " << aoki << " " << tak << endl;
    return (tak < aoki);  
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> x >> p;
    if(p == 100){
        cout << (x + 1) / 2 << endl;
        return 0;
    }
    double l = 0.0, r = 1e18;
    rep(i, 0, 100){
        double mid = (l + r) / 2;
        if(f(mid)) r = mid;
        else l = mid;
    }
    printf("%.15f\n", l);
}

Submission Info

Judge Result