Submission #481331

#	Time	Username	Problem	Language	Result	Execution time	Memory
481331		rainboy	Lampice (COCI19_lampice)	C11	17 / 110	5061 ms	6136 KiB

lampice

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

#define N	50000

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;
}

char cc[N + 1]; int d_;

void dfs(int p1, int i1, int p2, int i2, int d) {
	int o1, o2;

	d_ = max(d_, d);
	for (o1 = eo[i1]; o1--; ) {
		int j1 = ej[i1][o1];

		for (o2 = eo[i2]; o2--; ) {
			int j2 = ej[i2][o2];

			if (j1 != p1 && j2 != p2 && (i1 != i2 || j1 < j2) && cc[j1] == cc[j2])
				dfs(i1, j1, i2, j2, d + 2);
		}
	}
}

int main() {
	static int ii[N - 1], jj[N - 1];
	int n, h, i, j;

	scanf("%d%s", &n, cc);
	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--;
		ii[h] = i, jj[h] = j;
		append(i, j), append(j, i);
	}
	for (i = 0; i < n; i++)
		dfs(-1, i, -1, i, 1);
	for (h = 0; h < n - 1; h++)
		if (cc[ii[h]] == cc[jj[h]])
			dfs(ii[h], jj[h], jj[h], ii[h], 2);
	printf("%d\n", d_);
	return 0;
}

Compilation message (stderr)

lampice.c: In function 'append':
lampice.c:13:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   13 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
lampice.c: In function 'main':
lampice.c:40:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |  scanf("%d%s", &n, cc);
      |  ^~~~~~~~~~~~~~~~~~~~~
lampice.c:44:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 17 / 17
• Subtask 2: 0 / 25
• Subtask 3: 0 / 31
• Subtask 4: 0 / 37