Submission #550679

#	Time	Username	Problem	Language	Result	Execution time	Memory
550679		rainboy	도로 개발 (JOI15_road_development)	C11	100 / 100	186 ms	26288 KiB

road_development

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

#define N	100000
#define Q	300000

int ds[N];

int find(int i) {
	return ds[i] < 0 ? i : (ds[i] = find(ds[i]));
}

void join(int i, int j) {
	i = find(i);
	j = find(j);
	if (i == j)
		return;
	if (ds[i] > ds[j])
		ds[i] = j;
	else {
		if (ds[i] == ds[j])
			ds[i]--;
		ds[j] = i;
	}
}

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], pp_[N], qq[N], ta[N], tb[N];

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

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

		if (j != p) {
			int k = dfs1(i, j, d + 1);

			s += k;
			if (k_ < k)
				k_ = k, j_ = j;
		}
	}
	qq[i] = j_;
	tb[i] = time;
	return s;
}

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

	j_ = qq[i], qq[i] = q;
	if (j_ != -1)
		dfs2(i, j_, q);
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

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

char marked[N];

int find_(int i) {
	return !marked[i] ? i : (pp_[i] = find_(pp_[i]));
}

int ft[N];

void update(int i, int n, int x) {
	while (i < n) {
		ft[i] += x;
		i |= i + 1;
	}
}

int query(int i) {
	int x = 0;

	while (i >= 0) {
		x += ft[i];
		i &= i + 1, i--;
	}
	return x;
}

int main() {
	static int tt[Q], ii[Q], jj[Q], ans[Q];
	int n, q, h, i, j, a;

	scanf("%d%d", &n, &q);
	for (i = 0; i < n; i++)
		ej[i] = (int *) malloc(2 * sizeof *ej[i]);
	memset(ds, -1, n * sizeof *ds);
	for (h = 0; h < q; h++) {
		scanf("%d%d%d", &tt[h], &ii[h], &jj[h]), ii[h]--, jj[h]--;
		ans[h] = find(ii[h]) == find(jj[h]) ? 0 : -1;
		if (tt[h] == 1 && ans[h] == -1) {
			join(ii[h], jj[h]);
			append(ii[h], jj[h]), append(jj[h], ii[h]);
		}
	}
	for (i = 0; i < n; i++)
		if (ds[i] < 0)
			dfs1(-1, i, 0), dfs2(-1, i, i);
	for (h = 0; h < q; h++)
		if (ans[h] != -1) {
			i = ii[h], j = jj[h], a = lca(i, j);
			if (tt[h] == 1) {
				while (dd[i = find_(i)] > dd[a])
					marked[i] = 1, update(ta[i], n, 1), update(tb[i], n, -1);
				while (dd[j = find_(j)] > dd[a])
					marked[j] = 1, update(ta[j], n, 1), update(tb[j], n, -1);
			} else
				ans[h] = (dd[i] + dd[j] - dd[a] * 2) - (query(ta[i]) + query(ta[j]) - query(ta[a]) * 2);
		}
	for (h = 0; h < q; h++)
		if (tt[h] == 2)
			printf("%d\n", ans[h]);
	return 0;
}

Compilation message (stderr)

road_development.c: In function 'append':
road_development.c:33:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   33 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
road_development.c: In function 'main':
road_development.c:115:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  115 |  scanf("%d%d", &n, &q);
      |  ^~~~~~~~~~~~~~~~~~~~~
road_development.c:120:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  120 |   scanf("%d%d%d", &tt[h], &ii[h], &jj[h]), ii[h]--, jj[h]--;
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 25 / 25
• Subtask 3: 25 / 25
• Subtask 4: 25 / 25
• Subtask 5: 15 / 15