Submission #767605

#	Time	Username	Problem	Language	Result	Execution time	Memory
767605		rainboy	Marriage questions (IZhO14_marriage)	C11	100 / 100	284 ms	1100 KiB

marriage

/* https://oj.uz/submission/100855 (Benq) */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define NU	30000
#define NV	2000

unsigned int X = 12345;

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

int nu, nv;
int *eu[NV], eo[NV], el[NV], er[NV];
int uu[NV], vv[NU]; char visited[NV];

void append(int v, int u) {
	int o = eo[v]++;

	if (o >= 2 && (o & o - 1) == 0)
		eu[v] = (int *) realloc(eu[v], o * 2 * sizeof *eu[v]);
	eu[v][o] = u;
}

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 (ii[j] < 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 dfs(int v) {
	int o;

	if (visited[v])
		return 0;
	visited[v] = 1;
	for (o = el[v]; o < er[v]; o++) {
		int u = eu[v][o], w = vv[u];

		if (w == -1 || dfs(w)) {
			uu[v] = u, vv[u] = v;
			return 1;
		}
	}
	return 0;
}

int check() {
	int v;

	for (v = 0; v < nv; v++)
		if (uu[v] == -1) {
			memset(visited, 0, nv * sizeof *visited);
			if (!dfs(v))
				return 0;
		}
	return 1;
}

int main() {
	int m, h, l, r, u, v, ans;

	scanf("%d%d%d", &nu, &nv, &m);
	for (v = 0; v < nv; v++)
		eu[v] = (int *) malloc(2 * sizeof *eu[v]);
	for (h = 0; h < m; h++) {
		scanf("%d%d", &u, &v), u--, v--;
		append(v, u);
	}
	for (v = 0; v < nv; v++)
		sort(eu[v], 0, eo[v]);
	memset(uu, -1, nv * sizeof *uu), memset(vv, -1, nu * sizeof *vv);
	ans = 0;
	for (l = 0, r = -1; l < nu; l++) {
		while (r < nu && !check()) {
			r++;
			for (v = 0; v < nv; v++)
				if (er[v] < eo[v] && eu[v][er[v]] == r)
					er[v]++;
		}
		ans += nu - r;
		for (v = 0; v < nv; v++) {
			if (el[v] < eo[v] && eu[v][el[v]] == l)
				el[v]++;
			if (uu[v] == l)
				uu[v] = -1;
		}
	}
	printf("%d\n", ans);
	return 0;
}

Compilation message (stderr)

marriage.c: In function 'append':
marriage.c:22:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   22 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
marriage.c: In function 'main':
marriage.c:78:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   78 |  scanf("%d%d%d", &nu, &nv, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
marriage.c:82:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |   scanf("%d%d", &u, &v), u--, v--;
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100