Submission #545938

#	Time	Username	Problem	Language	Result	Execution time	Memory
545938		rainboy	Spring cleaning (CEOI20_cleaning)	C11	100 / 100	111 ms	16164 KiB

cleaning

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

#define N	100000

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 dd[N], pp[N], qq[N], sz[N], ta[N], dp[N];

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

	dd[i] = d, pp[i] = p, ta[i] = time++;
	dp[i] = eo[i] == 1;
	j_ = -1, sz[i] = 1;
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p) {
			dfs1(i, j, d + 1);
			if (j_ == -1 || sz[j_] < sz[j])
				j_ = j;
			sz[i] += sz[j];
			dp[i] += dp[j];
		}
	}
	if (j_ != -1)
		qq[j_] = -1;
}

int ans;

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

	if (p != -1) {
		ans += dp[i] % 2 == 0 ? 2 : 1;
		dp[i] = dp[p] + (dp[i] % 2 == 0 ? -1 : 1);
	} else
		dp[i] = 0;
	qq[i] = qq[i] ? qq[pp[i]] : i;
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p)
			dfs2(i, j);
	}
}

int lca(int i, int j) {
	while (qq[i] != qq[j])
		if (dd[qq[i]] > dd[qq[j]])
			i = pp[qq[i]];
		else
			j = pp[qq[j]];
	return dd[i] < dd[j] ? i : j;
}

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 (ii[j] == i_)
				j++;
			else if (ta[ii[j]] < ta[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 main() {
	int n, q, h, i, j, l, r;

	scanf("%d%d", &n, &q);
	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);
	}
	l = 0, r = -1;
	for (i = 0; i < n; i++)
		if (eo[i] == 1)
			l++;
		else
			r = i;
	dfs1(-1, r, 0);
	dfs2(-1, r);
	while (q--) {
		static int kk[N], ii[N], qu[N];
		int k, k_, h, cnt, ans_;

		scanf("%d", &k);
		for (h = 0; h < k; h++) {
			scanf("%d", &ii[h]), ii[h]--;
			kk[ii[h]]++;
		}
		ans_ = ans + k;
		k_ = 0;
		for (h = 0; h < k; h++) {
			if (kk[ii[h]] && (kk[ii[h]] - (eo[ii[h]] == 1 ? 1 : 0)) % 2 != 0)
				ii[k_++] = ii[h];
			kk[ii[h]] = 0;
		}
		k = k_;
		if ((l + k) % 2 != 0) {
			printf("-1\n");
			continue;
		}
		sort(ii, 0, k);
		if (k != 0) {
			cnt = 0;
			if (r != ii[0])
				qu[cnt++] = r, qu[cnt++] = ii[0];
			for (h = 1; h <= k; h++) {
				int a = h == k ? r : lca(ii[h - 1], ii[h]), flip;

				flip = 1;
				while (cnt >= 2 && dd[qu[cnt - 2]] >= dd[a]) {
					if (flip)
						ans_ += dp[qu[cnt - 1]] - dp[qu[cnt - 2]];
					flip ^= 1;
					cnt--;
				}
				if (cnt > 0) {
					if (flip)
						ans_ += dp[qu[cnt - 1]] - dp[a], qu[cnt - 1] = a;
					else
						cnt--;
					qu[cnt++] = ii[h];
				} else
					qu[cnt++] = a, qu[cnt++] = ii[h];
			}
		}
		printf("%d\n", ans_);
	}
	return 0;
}

Compilation message (stderr)

cleaning.c: In function 'append':
cleaning.c:18:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   18 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
cleaning.c: In function 'main':
cleaning.c:97:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |  scanf("%d%d", &n, &q);
      |  ^~~~~~~~~~~~~~~~~~~~~
cleaning.c:101:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  101 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~
cleaning.c:116:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  116 |   scanf("%d", &k);
      |   ^~~~~~~~~~~~~~~
cleaning.c:118:4: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  118 |    scanf("%d", &ii[h]), ii[h]--;
      |    ^~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 0
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 16 / 16
• Subtask 5: 19 / 19
• Subtask 6: 17 / 17
• Subtask 7: 30 / 30