Submission #439809

#	Time	Username	Problem	Language	Result	Execution time	Memory
439809		rainboy	Mag (COCI16_mag)	C11	24 / 120	496 ms	141500 KiB

mag

#include <stdio.h>
#include <stdlib.h>

#define N	1000000
#define INF	0x3f3f3f3f

int min(int a, int b) { return a < b ? a : b; }
int max(int a, int b) { return a > b ? a : b; }

int *ej[N], eo[N];

void append(int i, int j) {
	int o = eo[i]++;

	if (o >= 2 && (o & o - 1) == 0)
		ej[i] = (int *) realloc(ej[i], o * 2 * sizeof *ej[i]);
	ej[i][o] = j;
}

int aa[N], kk[N];

void dfs1(int p, int i) {
	int o, k;

	k = 0;
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p) {
			dfs1(i, j);
			k = max(k, kk[j]);
		}
	}
	kk[i] = aa[i] == 1 ? k + 1 : 0;
}

int p_, q_;

void dfs2(int p, int i, int k) {
	int o, k1, k2, j1;

	if (aa[i] == 1) {
		q_ = max(q_, k + 1);
		k1 = k2 = k, j1 = -1;
		for (o = eo[i]; o--; ) {
			int j = ej[i][o];

			if (j != p) {
				if (k1 < kk[j])
					k2 = k1, k1 = kk[j], j1 = j;
				else if (k2 < kk[j])
					k2 = kk[j];
			}
		}
		k1++, k2++;
	} else
		k1 = k2 = 0, j1 = -1;
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p)
			dfs2(i, j, j == j1 ? k2 : k1);
	}
}

int main() {
	int n, h, i, j;

	scanf("%d", &n);
	for (i = 0; i < n; i++)
		ej[i] = (int *) malloc(2 * sizeof *ej[i]);
	for (h = 0; h < n - 1; h++) {
		scanf("%d%d", &i, &j), i--, j--;
		append(i, j), append(j, i);
	}
	for (i = 0; i < n; i++)
		scanf("%d", &aa[i]);
	p_ = 1;
	dfs1(-1, 0), dfs2(-1, 0, 0);
	if (q_ == 0) {
		p_ = INF, q_ = 1;
		for (i = 0; i < n; i++)
			p_ = min(p_, aa[i]);
	}
	printf("%d/%d\n", p_, q_);
	return 0;
}

Compilation message (stderr)

mag.c: In function 'append':
mag.c:15:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   15 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
mag.c: In function 'main':
mag.c:69:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
mag.c:73:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~
mag.c:77:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |   scanf("%d", &aa[i]);
      |   ^~~~~~~~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 0 / 12
• Subtask 3: 0 / 12
• Subtask 4: 0 / 12
• Subtask 5: 0 / 12
• Subtask 6: 0 / 12
• Subtask 7: 0 / 12
• Subtask 8: 0 / 12
• Subtask 9: 0 / 12
• Subtask 10: 12 / 12