Submission #904258

#	Time	Username	Problem	Language	Result	Execution time	Memory
904258		rainboy	Robot Race (CPSPC17_race)	C11	20 / 100	2417 ms	79512 KiB

Main

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

#define N	1000
#define M	1000
#define Q	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; }

void append(int **ej, int *eo, 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 tt[N * M + 1][2], pp[N * M + 1], sz[N * M + 1];

int dir(int u) {
	return tt[pp[u]][0] == u ? 0 : 1;
}

int is_root(int u) {
	return pp[u] == 0 || tt[pp[u]][dir(u)] != u;
}

void pul(int u) {
	sz[u] = sz[tt[u][0]] + sz[tt[u][1]] + 1;
}

void attach(int u, int v, int d) {
	if (u)
		tt[u][d] = v, pul(u);
	if (v)
		pp[v] = u;
}

void rotate(int u) {
	int v = pp[u], w = pp[v], du = dir(u), dv = dir(v), top = is_root(v);

	attach(v, tt[u][du ^ 1], du);
	attach(u, v, du ^ 1);
	if (top)
		pp[u] = w;
	else
		attach(w, u, dv);
}

void splay(int u) {
	while (!is_root(u)) {
		if (!is_root(pp[u]))
			rotate(dir(u) == dir(pp[u]) ? pp[u] : u);
		rotate(u);
	}
}

void expose(int u) {
	int v, w;

	for (v = u, w = 0; v; w = v, v = pp[v])
		splay(v), attach(v, w, 1);
	splay(u);
}

void link(int u, int v) {
	expose(v), expose(u);
	attach(u, v, 1);
}

void cut(int u, int v) {
	expose(v), expose(u);
	attach(u, 0, 1), pp[v] = 0;
}

int ancestor(int u, int k) {
	expose(u);
	while (1)
		if (k < sz[tt[u][1]])
			u = tt[u][1];
		else if (k > sz[tt[u][1]])
			k -= sz[tt[u][1]] + 1, u = tt[u][0];
		else {
			splay(u);
			return u;
		}
}

int main() {
	static char cc[N][M + 1];
	static int ii1[Q], jj1[Q], kk1[Q], ii2[Q], jj2[Q], kk2[Q], dp[N][M], dq[N][M], *eij[N + M], eo[N + M], *eh[N + M], eo_[N + M];
	static char active[N][M], yes[Q];
	int n, m, q, h, i, i1, i2, j, j1, j2, ij, k, k1, k2, r, o;

	scanf("%d%d%d", &n, &m, &q);
	for (i = 0; i < n; i++)
		scanf("%s", cc[i]);
	for (h = 0; h < q; h++) {
		scanf("%d%d%d%d", &ii1[h], &jj1[h], &ii2[h], &jj2[h]), ii1[h]--, jj1[h]--, ii2[h]--, jj2[h]--;
		kk1[h] = ii1[h] + jj1[h], kk2[h] = ii2[h] + jj2[h];
	}
	for (i = 0; i < n; i++)
		for (j = 0; j < m; j++)
			if (cc[i][j] == '#')
				dp[i][j] = INF;
			else {
				dp[i][j] = i + j;
				if (i > 0)
					dp[i][j] = min(dp[i][j], dp[i - 1][j]);
				if (j > 0)
					dp[i][j] = min(dp[i][j], dp[i][j - 1]);
			}
	for (i = n - 1; i >= 0; i--)
		for (j = m - 1; j >= 0; j--)
			if (cc[i][j] == '#')
				dq[i][j] = -1;
			else {
				dq[i][j] = i + j;
				if (i + 1 < n)
					dq[i][j] = max(dq[i][j], dq[i + 1][j]);
				if (j + 1 < m)
					dq[i][j] = max(dq[i][j], dq[i][j + 1]);
			}
	for (k = 0; k < n + m; k++)
		eij[k] = (int *) malloc(2 * sizeof *eij[k]);
	for (i = 0; i < n; i++)
		for (j = 0; j < m; j++)
			if (cc[i][j] == '.')
				append(eij, eo, dq[i][j], i * m + j);
	for (k = 0; k < n + m; k++)
		eh[k] = (int *) malloc(2 * sizeof *eh[k]);
	for (h = 0; h < q; h++) {
		i1 = ii1[h], j1 = jj1[h], k1 = kk1[h], i2 = ii2[h], j2 = jj2[h], k2 = kk2[h];
		if (k1 > k2 || dq[i1][j1] < k2 || dp[i2][j2] > k1)
			yes[h] = 0;
		else
			yes[h] = 1, append(eh, eo_, k2, h);
	}
	for (r = 0; r < 2; r++) {
		for (i = 0; i < n; i++)
			memset(active[i], 0, m * sizeof *active[i]);
		memset(pp, 0, n * m * sizeof *pp);
		for (i = 1; i <= n * m; i++)
			tt[i][0] = tt[i][1] = 0, sz[i] = 1;
		for (k = n + m - 1; k >= 0; k--) {
			for (o = eo[k]; o--; ) {
				ij = eij[k][o], i = ij / m, j = ij % m;
				active[i][j] = 1;
				if (r == 0) {
					if (i + 1 < n && active[i + 1][j])
						link((i + 1) * m + j + 1, i * m + j + 1);
					else if (j + 1 < m && active[i][j + 1])
						link(i * m + (j + 1) + 1, i * m + j + 1);
					if (i > 0 && active[i - 1][j]) {
						if (j + 1 < m && active[i - 1][j + 1])
							cut((i - 1) * m + (j + 1) + 1, (i - 1) * m + j + 1);
						link(i * m + j + 1, (i - 1) * m + j + 1);
					}
					if (j > 0 && active[i][j - 1] && (i + 1 == n || !active[i + 1][j - 1]))
						link(i * m + j + 1, i * m + (j - 1) + 1);
				} else {
					if (j + 1 < m && active[i][j + 1])
						link(i * m + (j + 1) + 1, i * m + j + 1);
					else if (i + 1 < n && active[i + 1][j])
						link((i + 1) * m + j + 1, i * m + j + 1);
					if (j > 0 && active[i][j - 1]) {
						if (i + 1 < n && active[i + 1][j - 1])
							cut((i + 1) * m + (j - 1) + 1, i * m + (j - 1) + 1);
						link(i * m + j + 1, i * m + (j - 1) + 1);
					}
					if (i > 0 && active[i - 1][j] && (j + 1 == m || !active[i - 1][j + 1]))
						link(i * m + j + 1, (i - 1) * m + j + 1);
				}
			}
			for (o = eo_[k]; o--; ) {
				h = eh[k][o], i1 = ii1[h], j1 = jj1[h], k1 = kk1[h], i2 = ii2[h], j2 = jj2[h], k2 = kk2[h];
				ij = ancestor(i1 * m + j1 + 1, k2 - k1) - 1;
				if ((r == 0 ? ij < i2 * m + j2 : ij > i2 * m + j2))
					yes[h] = 0;
			}
		}
	}
	for (h = 0; h < q; h++)
		printf(yes[h] ? "YES\n" : "NO\n");
	return 0;
}

Compilation message (stderr)

Main.c: In function 'append':
Main.c:16:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   16 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
Main.c: In function 'main':
Main.c:98:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |  scanf("%d%d%d", &n, &m, &q);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.c:100:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  100 |   scanf("%s", cc[i]);
      |   ^~~~~~~~~~~~~~~~~~
Main.c:102:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  102 |   scanf("%d%d%d%d", &ii1[h], &jj1[h], &ii2[h], &jj2[h]), ii1[h]--, jj1[h]--, ii2[h]--, jj2[h]--;
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 0 / 80