oj.uz

답안 #482430

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
482430 2021-10-24T14:34:51 Z rainboy Papričice (COCI20_papricice) C
110 / 110
 163 ms 22892 KB 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define N	200000

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

int dist(int a, int b, int c) {
	return max(max(a, b), c) - min(min(a, b), c);
}

int *ej[N], eo[N], 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 ta[N], tb[N], c;
int rr[N], sz[N];

void dfs1(int p, int i) {
	static int time;
	int o, centroid;

	ta[i] = time++;
	sz[i] = 1, centroid = 1;
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p) {
			dfs1(i, j);
			sz[i] += sz[j];
			if (sz[j] * 2 > n)
				centroid = 0;
		}
	}
	if ((n - sz[i]) * 2 > n)
		centroid = 0;
	if (centroid)
		c = i;
	tb[i] = time;
}

void dfs2(int p, int r, int i) {
	int o;

	rr[i] = r, sz[i] = 1;
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p) {
			dfs2(i, r, j);
			sz[i] += sz[j];
		}
	}
}

int main() {
	static int rr_[N], dp1[N], dp2[N], dq1[N], dq2[N];
	int h, i, j, s, o, ans;

	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);
	}
	dfs1(-1, 0);
	for (o = eo[c]; o--; ) {
		j = ej[c][o];
		dfs2(c, j, j);
	}
	memset(rr_, -1, n * sizeof *rr_);
	for (i = 0; i < n; i++)
		if (rr_[sz[i]] == -1)
			rr_[sz[i]] = rr[i];
		else if (rr_[sz[i]] != rr[i])
			rr_[sz[i]] = -2;
	for (s = 0; s < n; s++) {
		dp1[s] = s == 0 ? -1 : dp1[s - 1], dp2[s] = s == 0 ? -1 : dp2[s - 1];
		if (rr_[s] != -1) {
			if (dp1[s] == -1 || rr_[dp1[s]] != rr_[s])
				dp2[s] = dp1[s];
			dp1[s] = s;
		}
	}
	for (s = n - 1; s >= 0; s--) {
		dq1[s] = s + 1 == n ? n : dq1[s + 1], dq2[s] = s + 1 == n ? n : dq2[s + 1];
		if (rr_[s] != -1) {
			if (dq1[s] == n || rr_[dq1[s]] != rr_[s])
				dq2[s] = dq1[s];
			dq1[s] = s;
		}
	}
	ans = n + 1;
	for (i = 0; i < n; i++)
		if (i != c) {
			int s, s_;

			if (i != rr[i])
				ans = min(ans, dist(n - sz[rr[i]], sz[rr[i]] - sz[i], sz[i]));
			s = (n - sz[i]) / 2;
			if ((s_ = dp1[s]) != -1 && rr_[s_] != rr[i])
				ans = min(ans, dist(sz[i], s_, n - sz[i] - s_));
			else if ((s_ = dp2[s]) != -1)
				ans = min(ans, dist(sz[i], s_, n - sz[i] - s_));
			if ((s_ = dq1[s]) != n && rr_[s_] != rr[i])
				ans = min(ans, dist(sz[i], s_, n - sz[i] - s_));
			else if ((s_ = dq2[s]) != n)
				ans = min(ans, dist(sz[i], s_, n - sz[i] - s_));
		}
	printf("%d\n", ans);
	return 0;
}

Compilation message

papricice.c: In function 'append':
papricice.c:19:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   19 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
papricice.c: In function 'main':
papricice.c:68:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
papricice.c:72:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

Subtask #1
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 0 ms 332 KB Output is correct
3 Correct 0 ms 332 KB Output is correct
4 Correct 0 ms 332 KB Output is correct
5 Correct 0 ms 332 KB Output is correct

Subtask #2
35.0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 0 ms 332 KB Output is correct
3 Correct 0 ms 332 KB Output is correct
4 Correct 0 ms 332 KB Output is correct
5 Correct 0 ms 332 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 2 ms 460 KB Output is correct
10 Correct 1 ms 460 KB Output is correct

Subtask #3
60.0 / 60.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 0 ms 332 KB Output is correct
3 Correct 0 ms 332 KB Output is correct
4 Correct 0 ms 332 KB Output is correct
5 Correct 0 ms 332 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 2 ms 460 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 150 ms 16308 KB Output is correct
12 Correct 163 ms 18628 KB Output is correct
13 Correct 128 ms 19132 KB Output is correct
14 Correct 131 ms 18968 KB Output is correct
15 Correct 152 ms 18624 KB Output is correct
16 Correct 100 ms 18628 KB Output is correct
17 Correct 139 ms 18756 KB Output is correct
18 Correct 137 ms 22892 KB Output is correct
19 Correct 140 ms 19032 KB Output is correct
20 Correct 131 ms 18660 KB Output is correct