oj.uz

답안 #545910

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
545910 2022-04-05T16:08:33 Z rainboy Mousetrap (CEOI17_mousetrap) C
100 / 100
 887 ms 159604 KB 
#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; }

unsigned int X = 12345;

int rand_() {
	return (X *= 3) >> 1;
}

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 dp[N];

void dfs_(int p, int i, int k) {
	int o, mx1, mx2;

	k += eo[i] - 1, mx1 = mx2 = k;
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p) {
			dfs_(i, j, k);
			if (mx1 < dp[j])
				mx2 = mx1, mx1 = dp[j];
			else if (mx2 < dp[j])
				mx2 = dp[j];
		}
	}
	dp[i] = mx2;
}

void sort(int *ii, int l, int r) {
	while (l < r) {
		int i = l, j = l, k = r, i_ = ii[l + rand_() % (r - l)], tmp;

		while (j < k)
			if (dp[ii[j]] == dp[i_])
				j++;
			else if (dp[ii[j]] > dp[i_]) {
				tmp = ii[i], ii[i] = ii[j], ii[j] = tmp;
				i++, j++;
			} else {
				k--;
				tmp = ii[j], ii[j] = ii[k], ii[k] = tmp;
			}
		sort(ii, l, i);
		l = k;
	}
}

int qu[N], gg[N], jj[N], n, m, l, ans; char path[N];

int solve() {
	int g, g_, h;

	for (g = 0, g_ = 0, h = 0; g <= l; g++) {
		while (h < m && dp[jj[h]] + g_ <= ans) {
			h++;
			if (h < m && gg[jj[h]] != gg[jj[h - 1]])
				g_ = g;
		}
		if (h == m)
			return 1;
		if (gg[jj[h]] < g || g == ans)
			return 0;
		h++;
		if (h < m && gg[jj[h]] != gg[jj[h - 1]])
			g_ = g + 1;
	}
	return 1;
}

int dfs(int p, int i, int t) {
	int o;

	qu[l++] = i, path[i] = 1;
	if (i == t) {
		int d, g, lower, upper;

		l--, d = 0;
		for (g = 0; g < l; g++) {
			i = qu[g];
			d += eo[i] - (g == 0 ? 1 : 2);
		}
		m = 0;
		for (g = 0; g < l; g++) {
			int m_;

			i = qu[g];
			m_ = m;
			for (o = eo[i]; o--; ) {
				int j = ej[i][o];

				if (!path[j]) {
					dfs_(i, j, d);
					gg[j] = g, jj[m_] = j, m_++;
				}
			}
			sort(jj, m, m_);
			m = m_;
			d -= eo[i] - (g == 0 ? 1 : 2);
		}
		lower = -1, upper = n;
		while (upper - lower > 1) {
			ans = (lower + upper) / 2;
			if (solve())
				upper = ans;
			else
				lower = ans;
		}
		ans = upper;
		return 1;
	}
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p && dfs(i, j, t))
			return 1;
	}
	l--, path[i] = 0;
	return 0;
}

int main() {
	int t, m, h, i, j;

	scanf("%d%d%d", &n, &t, &m), t--, m--;
	if (m == t) {
		printf("0\n");
		return 0;
	}
	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);
	}
	dfs(-1, m, t);
	printf("%d\n", ans);
	return 0;
}

Compilation message

mousetrap.c: In function 'append':
mousetrap.c:21:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   21 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
mousetrap.c: In function 'main':
mousetrap.c:141:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  141 |  scanf("%d%d%d", &n, &t, &m), t--, m--;
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~
mousetrap.c:149:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  149 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 260 KB Output is correct
4 Correct 0 ms 340 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 340 KB Output is correct
8 Correct 0 ms 340 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 308 ms 61492 KB Output is correct
2 Correct 271 ms 55484 KB Output is correct
3 Correct 767 ms 63820 KB Output is correct
4 Correct 338 ms 31868 KB Output is correct
5 Correct 751 ms 63852 KB Output is correct
6 Correct 764 ms 63752 KB Output is correct

Subtask #3
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 260 KB Output is correct
4 Correct 0 ms 340 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 340 KB Output is correct
8 Correct 0 ms 340 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 340 KB Output is correct
12 Correct 1 ms 340 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 1 ms 468 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 ms 340 KB Output is correct
17 Correct 1 ms 340 KB Output is correct
18 Correct 1 ms 340 KB Output is correct
19 Correct 1 ms 340 KB Output is correct
20 Correct 1 ms 296 KB Output is correct
21 Correct 1 ms 340 KB Output is correct
22 Correct 1 ms 340 KB Output is correct

Subtask #4
35.0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 260 KB Output is correct
4 Correct 0 ms 340 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 340 KB Output is correct
8 Correct 0 ms 340 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 308 ms 61492 KB Output is correct
12 Correct 271 ms 55484 KB Output is correct
13 Correct 767 ms 63820 KB Output is correct
14 Correct 338 ms 31868 KB Output is correct
15 Correct 751 ms 63852 KB Output is correct
16 Correct 764 ms 63752 KB Output is correct
17 Correct 0 ms 340 KB Output is correct
18 Correct 1 ms 340 KB Output is correct
19 Correct 1 ms 340 KB Output is correct
20 Correct 1 ms 468 KB Output is correct
21 Correct 1 ms 340 KB Output is correct
22 Correct 1 ms 340 KB Output is correct
23 Correct 1 ms 340 KB Output is correct
24 Correct 1 ms 340 KB Output is correct
25 Correct 1 ms 340 KB Output is correct
26 Correct 1 ms 296 KB Output is correct
27 Correct 1 ms 340 KB Output is correct
28 Correct 1 ms 340 KB Output is correct
29 Correct 1 ms 340 KB Output is correct
30 Correct 288 ms 61612 KB Output is correct
31 Correct 302 ms 61556 KB Output is correct
32 Correct 345 ms 155580 KB Output is correct
33 Correct 405 ms 159604 KB Output is correct
34 Correct 782 ms 64060 KB Output is correct
35 Correct 828 ms 64020 KB Output is correct
36 Correct 852 ms 77580 KB Output is correct
37 Correct 887 ms 77596 KB Output is correct
38 Correct 771 ms 76740 KB Output is correct
39 Correct 698 ms 76704 KB Output is correct
40 Correct 658 ms 76676 KB Output is correct