Submission #15195

#	Time	Username	Problem	Language	Result	Execution time	Memory
15195		gs14004	맛있는 과자 (kriii3_A)	C++14	33 / 33	0 ms	1844 KiB

A

#include <cstdio>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
using namespace std;
typedef long long lint;

lint bino[44][44];

int main(){
	for(int i=0; i<44; i++){
		bino[i][0] = 1;
		for(int j=1; j<=i; j++){
			bino[i][j] = bino[i-1][j] + bino[i-1][j-1];
		}
	}
	int a, b, n;
	long long k;
	scanf("%d %d %d %lld",&a,&b,&n,&k);
	long double addi0 = log(1.0 * (a * a) / (a * a + b * b));
	long double addi1 = log(1.0 * (b * b) / (a * a + b * b));
	int p = 0;
	for(int i=0; i<=n; i++){
		if(bino[n][i] >= k){
			p = i;
			break;
		}
		k -= bino[n][i];
	}
	if(addi0 > addi1) swap(addi0, addi1);
	cout << setprecision(30) << p * addi0 + (n - p ) * addi1 + log(a * b * 0.5);
}

• Subtask 1: 10 / 10
• Subtask 2: 23 / 23