Submission #15188

#	Time	Username	Problem	Language	Result	Execution time	Memory
15188		myungwoo	맛있는 과자 (kriii3_A)	C++14	33 / 33	0 ms	1204 KiB

A

#pragma warning(disable:4996)

#include <stdio.h>
#include <math.h>
#include <algorithm>
using namespace std;

double a, b, c;
int n;
long long k;

long long comb[41][41];

int main()
{
	scanf("%lf%lf%d%lld", &a, &b, &n, &k);
	c = sqrt(a*a + b*b);
	if (a>b) swap(a, b);
	a /= c; b /= c;

	comb[0][0] = 1;
	for (int i=1; i<=n; i++) {
		comb[i][0] = 1;
		for (int j=1; j<=i; j++) comb[i][j] = comb[i-1][j-1] + comb[i-1][j];
	}

	for (int i=n; i>=0; i--) {
		if (k <= comb[n][i]) {
			int ae = 2*(n-i)+1, be = 2*i+1;
			double ans = 2 * log(c) + ae * log(a) + be * log(b) - log(2.);
			printf("%.15lf\n", ans);

			break;
		}
		else k -= comb[n][i];
	}

	return 0;
}

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