Submission #15412

#	Time	Username	Problem	Language	Result	Execution time	Memory
15412		tlwpdus	맛있는 과자 (kriii3_A)	C++98	33 / 33	0 ms	1212 KiB

A

#include<stdio.h>
#include<math.h>

using namespace std;

long long pas[50][50];
int a, b, n;
long long k;

void input() {
	scanf("%d %d %d %lld", &a, &b, &n, &k);
	if (a > b) {
		int t = a;
		a = b;
		b = t;
	}
}

void init() {
	int i, j;
	for (i = 0; i <= n + 1; i++) {
		for (j = 0; j <= i; j++) {
			if (j == 0 || j == i) pas[i][j] = 1;
			else pas[i][j] = pas[i - 1][j] + pas[i - 1][j - 1];
		}
	}
}

void process() {
	int i;
	long long sum = 0;
	for (i = 0; i <= n; i++) {
		sum += pas[n][i];
		if (sum >= k) {
			break;
		}
	}
	double alog = log((double)(a*a) / (a*a + b*b)), blog = log((double)(b*b) / (a*a + b*b));
	double S = log((double)(a*b) / 2);
	printf("%.12lf\n", S + i*alog + (n - i)*blog);
}

int main() {
	input();
	init();
	process();
	return 0;
}

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