Submission #39234203

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Source Code Expand

#include <stdio.h>
#include <string.h>

int i_cmp (void *n1, void *n2) {
	int a = *(int *)n1;
	int b = *(int *)n2;
	if (a > b) {
		return 1;
	} else if (a < b) {
		return -1;
	} else {
		return 0;
	}
}

void swap_all (void *n1, void *n2, size_t size) {
	char tmp[size];
	memcpy(tmp, n1, size);
	memcpy(n1, n2, size);
	memcpy(n2, tmp, size);
}

void heapsort (void *base, size_t num, size_t size, int (* cmpfunc)(void *, void *), int type) {
	for (int i = 1; num > i; i++) {
		for (int j = i; j > 0;) {
			if (type == 1) {
				if (cmpfunc((char *)(base + size * j), (char *)(base + size * ((j - 1) / 2))) == 1) {
					swap_all((char *)(base + size * j), (char *)(base + size * ((j - 1) / 2)), size);
					j = (j - 1) / 2;
				} else {
					break;
				}
			} else {
				if (cmpfunc((char *)(base + size * j), (char *)(base + size * ((j - 1) / 2))) == -1) {
					swap_all((char *)(base + size * j), (char *)(base + size * ((j - 1) / 2)), size);
					j = (j - 1) / 2;
				} else {
					break;
				}
			}
		}
	}

	for (int i = num - 1; i > 0; i--) {
		swap_all((char *)base, (char *)(base + size * i), size);
		for (int j = 0; ;) {
			int lch = 2 * j + 1, rch = 2 * j + 2, rep;
			if (i > rch) {
				if (type == 1) {
					rep = (cmpfunc((char *)(base + size * lch), (char *)(base + size * rch)) == 1 ? lch : rch);
				} else {
					rep = (cmpfunc((char *)(base + size * lch), (char *)(base + size * rch)) == -1 ? lch : rch);
				}
			} else if (rch == i) {
				rep = lch;
			} else {
				break;
			}
			if (type == 1) {
				if (cmpfunc((char *)(base + size * j), (char *)(base + size * rep)) == -1) {
					swap_all((char *)(base + size * j), (char *)(base + size * rep), size);
					j = rep;
				} else {
					break;
				}
			} else {
				if (cmpfunc((char *)(base + size * j), (char *)(base + size * rep)) == 1) {
					swap_all((char *)(base + size * j), (char *)(base + size * rep), size);
					j = rep;
				} else {
					break;
				}
			}
		}
	}
}

int main (void) {
	int n;
	scanf("%i", &n);

	int x[5 * n];
	for (int i = 0; 5 * n > i; i++) {
		scanf("%i", &x[i]);
	}

	heapsort(x, 5 * n, sizeof(int), i_cmp, 1);

	/*
	for (int i = 0; 5 * n > i; i++) {
		printf("%i ", x[i]);
	}
	printf("\n");
	// */

	int sum = 0;
	for (int i = 0; 3 * n > i; i++) {
		sum += x[n + i];
	}
	double ans = (double)sum / (3 * n);
	printf("%f", ans);

	return 0;
}

Submission Info

Judge Result