Submission #694973

#	Time	Username	Problem	Language	Result	Execution time	Memory
694973		rainboy	Telegraph (JOI16_telegraph)	C11	100 / 100	35 ms	3532 KiB

telegraph

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

#define N	100000
#define INF	0x3f3f3f3f

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

int main() {
	static int pp[N], cc1[N], cc2[N], jj[N];
	static char visited[N];
	int n, i, j, c, x;
	long long ans;

	scanf("%d", &n);
	memset(jj, -1, n * sizeof *jj);
	ans = 0;
	for (j = 0; j < n; j++) {
		scanf("%d%d", &i, &c), i--;
		pp[j] = i;
		if (cc1[i] < c)
			cc2[i] = cc1[i], cc1[i] = c, jj[i] = j;
		else if (cc2[i] < c)
			cc2[i] = c;
		ans += c;
	}
	for (i = 0; i < n; i++)
		ans -= cc1[i];
	for (i = 0; i < n; i++)
		if (!visited[i]) {
			j = i;
			while (!visited[j])
				visited[j] = 1, j = pp[j];
			if (visited[j] == 1) {
				x = INF, c = 0;
				while (visited[j] == 1) {
					if (jj[pp[j]] != j)
						x = 0;
					else
						x = min(x, cc1[pp[j]] - cc2[pp[j]]);
					visited[j] = 2, j = pp[j], c++;
				}
				if (c == n) {
					ans = 0;
					break;
				}
				ans += x;
			}
			j = i;
			while (visited[j] != 3)
				visited[j] = 3, j = pp[j];
		}
	printf("%lld\n", ans);
	return 0;
}

Compilation message (stderr)

telegraph.c: In function 'main':
telegraph.c:15:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
telegraph.c:19:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |   scanf("%d%d", &i, &c), i--;
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 30 / 30
• Subtask 3: 30 / 30
• Subtask 4: 30 / 30