Submission #15238

#	Time	Username	Problem	Language	Result	Execution time	Memory
15238		sujin	맛있는 과자 (kriii3_A)	C++98	33 / 33	0 ms	1196 KiB

A

#define _CRT_SECURE_NO_WARNINGS

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

long long combination(int n, int r){
	int p[40] = { 0 };
	for (int i = r + 1; i <= n; i++){
		int t = i;
		for (int j = 2; j <= t; j++){
			while (t % j == 0){
				t /= j;
				p[j]++;
			}
		}
	}
	for (int i = 1; i <= n - r; i++){
		int t = i;
		for (int j = 2; j <= t; j++){
			while (t % j == 0){
				t /= j;
				p[j]--;
			}
		}
	}
	long long x = 1;
	for (int i = 2; i < 40; i++)
		while (p[i]--)
			x *= i;
	return x;
}

int main(){
	int a, b, N;
	long long K;

	scanf("%d %d %d %lld", &a, &b, &N, &K);

	double A = double(a < b ? a : b);
	double B = double(a > b ? a : b);
	double C = hypot(A, B);

	long long p = 0;
	for (int i = 0; i < K; i++){
		p += combination(N, i);
		if (p >= K){
			double x = A * B / 2;
			for (int j = 0; j < N - i; j++)
				x *= B * B;
			for (int j = 0; j < i; j++)
				x *= A * A;
			for (int j = 0; j < N; j++)
				x /= C * C;
			printf("%.12lf", log(x));
			break;
		}
	}

	return 0;
}

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