제출 #592739

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
592739		rainboy	Stranded Far From Home (BOI22_island)	C11	100 / 100	235 ms	39476 KiB

island

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

#define N	200000

unsigned int X = 12345;

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

int aa[N];

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 (aa[ii[j]] == aa[i_])
				j++;
			else if (aa[ii[j]] < aa[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 *ej[N], eo[N], *ej_[N], eo_[N];

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 ds[N], rr[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 || rr[j] == -1)
		return;
	append(ej_, eo_, rr[i], rr[j]);
	if (ds[i] > ds[j])
		ds[i] = j, rr[j] = rr[i];
	else {
		if (ds[i] == ds[j])
			ds[i]--;
		ds[j] = i;
	}
}

long long sz[N];

void dfs1(int i) {
	int o;

	sz[i] = aa[i];
	for (o = eo_[i]; o--; ) {
		int j = ej_[i][o];

		dfs1(j);
		sz[i] += sz[j];
	}
}

char cc[N + 1];

void dfs2(int i) {
	int o;

	cc[i] = 1;
	for (o = eo_[i]; o--; ) {
		int j = ej_[i][o];

		if (sz[j] >= aa[i])
			dfs2(j);
	}
}

int main() {
	static int ii[N];
	int n, m, h, i, j, o;

	scanf("%d%d", &n, &m);
	for (i = 0; i < n; i++)
		scanf("%d", &aa[i]);
	for (i = 0; i < n; i++)
		ii[i] = i;
	sort(ii, 0, n);
	for (i = 0; i < n; i++)
		ej[i] = (int *) malloc(2 * sizeof *ej[i]);
	while (m--) {
		scanf("%d%d", &i, &j), i--, j--;
		append(ej, eo, i, j), append(ej, eo, j, i);
	}
	memset(ds, -1, n * sizeof *ds), memset(rr, -1, n * sizeof *rr);
	for (i = 0; i < n; i++)
		ej_[i] = (int *) malloc(2 * sizeof *ej_[i]);
	for (h = 0; h < n; h++) {
		i = ii[h];
		rr[i] = i;
		for (o = eo[i]; o--; ) {
			j = ej[i][o];
			join(i, j);
		}
	}
	i = rr[find(0)];
	dfs1(i), dfs2(i);
	for (i = 0; i < n; i++)
		cc[i] += '0';
	printf("%s\n", cc);
	return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

island.c: In function 'append':
island.c:39:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   39 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
island.c: In function 'main':
island.c:96:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   96 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
island.c:98:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |   scanf("%d", &aa[i]);
      |   ^~~~~~~~~~~~~~~~~~~
island.c:105:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 30 / 30
• Subtask 5: 35 / 35