Submission #16975

#	Time	Username	Problem	Language	Result	Execution time	Memory
16975		taehoon1018	초록색 삼각형 (YDX13_green)	C++98	0 / 1	0 ms	1084 KiB

C

#include <stdio.h>

double area(int x1, int y1, int x2, int y2, int x3, int y3)
{
	double res = (x1*y2 + x2*y3 + x3*y1 - x2*y1 - x3*y2 - x1*y3)/(double)2;
	if (res < 0)
		res = -res;

	return res;
}
int main(void)
{
	int x[2000] = { 0 };
	int y[2000] = { 0 };
	int N = 0,count = 0;
	double sum = 0;

	scanf("%d", &N);
	for (int i = 0; i < N; i++)
	{
		scanf("%d%d", &x[i], &y[i]);
	}
	if (N < 3)
	{
		printf("%.12f", 0);
		return 0;
	}
	for (int a = 0; a < N-2;a++)
	{
		for (int b = a+1; b < N - 1;b++)
		{
			for (int c = b+1; c < N;c++)
			{
				sum += area(x[a], y[a], x[b], y[b], x[c], y[c]);
				count++;
			}
		}
	}

	printf("%.12f\n", sum/count);

	return 0;
}

• Subtask 1: 0 / 1