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P4961 小埋与扫雷 - 洛谷 | 计算机科学教育新生态 (luogu.com.cn)
- 本题#17报RE错，是因为栈溢出，查询了资料之后发现，java主线程分配的栈块太小，递归深度太大就会发生这种问题，我们写爆搜不可避免要在Tle和爆栈边缘徘徊，这也是和c++相比一个比较弱势的点，那么有没有方法解决这一弱点呢？朋友别慌，有的，都有的
- 笔者查了下资料，发现我们可以直接开一个子线程，然后自己设置栈的空间大小，这一问题就解决啦
- 上代码
package shuati;
import java.io.*;
import java.util.*;
public class Main implements Runnable{
static StreamTokenizer cin = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
static PrintWriter cout = new PrintWriter(new OutputStreamWriter(System.out));
static int n, m;
static final int N = (int) (1e3 + 10);
static int[][] g = new int[N][N];
/*
cnt = 0 空格
cnt = 数字 雷
*/
static int[][] cnt = new int[N][N];
static boolean[][] str = new boolean[N][N];
static int[] dx = {1, 1, 0, -1, -1, -1, 0, 1};
static int[] dy = {0, 1, 1, 1, 0, -1, -1, -1};
static int ans;
public static void dfs(int x, int y) {
for (int i = 0; i < 8; i++) {
int nowx = dx[i] + x;
int nowy = dy[i] + y;
if(nowx >= 1 && nowx <= n && nowy >= 1 && nowy <= m) {
if(!str[nowx][nowy] && cnt[nowx][nowy] == 0 && g[nowx][nowy] == 0) {
str[nowx][nowy] = true;
dfs(nowx, nowy);
}
}
}
}
/*
是否统计进去, 统计周围8格全是数字或者雷的格子
*/
public static int solve(int x, int y) {
int num = 0;
for (int i = 0; i < 8; i++) {
int nowx = x + dx[i];
int nowy = y + dy[i];
if(nowx >= 1 && nowx <= n && nowy >= 1 && nowy <= m) {
if(cnt[nowx][nowy] == 0 && g[nowx][nowy] == 0){
num++;
break;
}
}
}
if(num == 1) return 0;
else return 1;
}
public static void main(String[] args) throws IOException {
new Thread(null, new Main(), "", 1 << 29).start();
}
@Override
public void run() {
try {
cin.nextToken();
n = (int) cin.nval;
cin.nextToken();
m = (int) cin.nval;
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= m; j++) {
cin.nextToken();
g[i][j] = (int) cin.nval;
}
}
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= m; j++) {
if(g[i][j] == 0) {
int num = 0;
for (int k = 0; k < 8; k++) {
int nowx = i + dx[k];
int nowy = j + dy[k];
if(nowx >= 1 && nowx <= n && nowy >= 1 && nowy <= m) {
if(g[nowx][nowy] == 1) num++;
}
}
cnt[i][j] = num;
}
}
}
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= m; j++) {
if(g[i][j] == 1) continue;
if(str[i][j]) continue;
if(cnt[i][j] == 0) {
str[i][j] = true;
dfs(i, j);
ans++;
continue;
}
int a = solve(i, j);
ans += a;
}
}
cout.println(ans);
cout.flush();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
Labyrinth - 洛谷 | 计算机科学教育新生态 (luogu.com.cn)
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.StreamTokenizer;
import java.util.*;
public class Main implements Runnable {
static Scanner scanner = new Scanner(System.in);
static PrintWriter cout = new PrintWriter(new OutputStreamWriter(System.out));
static int n, m, r, c, x, y;
static final int N = (int) (2e3 + 10);
static int[][] g = new int[N][N];
static Deque<Point> queue = new ArrayDeque<>();
static int[] dx = {0, 1, 0, -1, 0};
static int[] dy = {0, 0, 1, 0, -1};
static int[][] dist = new int[N][N];
public static void main(String[] args) {
new Thread(null, new Main(), "", 1 << 29).start();
}
public static int judge(int x) {
if(x == 4) {
return 1;
} else {
return 0;
}
}
public static void bfs() {
while (!queue.isEmpty()) {
Point point = queue.pollFirst();
int x_ = point.x;
int y_ = point.y;
for (int i = 1; i <= 4; i++) {
int nowx = x_ + dx[i];
int nowy = y_ + dy[i];
if (nowx < 1 || nowx > n || nowy < 1 || nowy > m || g[nowx][nowy] == 1) continue;
if (dist[x_][y_] + judge(i) >= dist[nowx][nowy] && dist[nowx][nowy] != -1) continue;
dist[nowx][nowy] = dist[x_][y_] + judge(i);
if (i == 4) {
queue.addLast(new Point(nowx, nowy));
} else {
queue.addFirst(new Point(nowx, nowy));
}
}
}
}
@Override
public void run() {
for(int i = 0; i < N; i++) {
Arrays.fill(dist[i], -1);
}
n = scanner.nextInt();
m = scanner.nextInt();
r = scanner.nextInt();
c = scanner.nextInt();
x = scanner.nextInt();
y = scanner.nextInt();
for (int i = 1; i <= n; i++) {
String s = scanner.next();
for (int j = 0; j < m; j++) {
if (s.charAt(j) == '*') g[i][j + 1] = 1;
}
}
queue.addFirst(new Point(r, c));
dist[r][c] = 0;
bfs();
int ans = 0;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if(dist[i][j] == -1) continue;
int a = dist[i][j];
int b = j - c + a;
if(a <= x && b <= y) ans++;
}
}
cout.println(ans);
cout.flush();
}
static class Point {
int x;
int y;
public Point(int x, int y) {
this.x = x;
this.y = y;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
}
}
P1294 高手去散步 - 洛谷 | 计算机科学教育新生态 (luogu.com.cn)
- 没啥特别的，唯一特别的可能就是无向图的搜索？？
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.StreamTokenizer;
import java.util.*;
public class Main implements Runnable{
static StreamTokenizer cin = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
static PrintWriter cout = new PrintWriter(new OutputStreamWriter(System.out));
static int n, m;
static Vector<Integer>[] node = new Vector[25];
static int[][] dist = new int[25][25];
static boolean[] str = new boolean[25];
static int ans;
public static int nextInt() throws IOException {
cin.nextToken();
return (int) cin.nval;
}
public static void dfs(int num, int dis) {
ans = Math.max(ans, dis);
for (Integer i : node[num]) {
if(!str[i]) {
str[i] = true;
dfs(i, dis + dist[num][i]);
str[i] = false;
}
}
}
public static void main(String[] args) {
new Thread(null, new Main(), "", 1 << 29).start();
}
@Override
public void run() {
try {
for(int i = 0; i < 25; i++) {
node[i] = new Vector<>();
}
n = nextInt();
m = nextInt();
for(int i = 1; i <= m; i++) {
int x = nextInt();
int y = nextInt();
int c = nextInt();
node[x].add(y);
node[y].add(x);
dist[x][y] = c;
dist[y][x] = c;
}
for(int i = 1; i <= n; i++) {
str[i] = true;
dfs(i, 0);
str[i] = false;
}
cout.println(ans);
cout.flush();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
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