求调 qaq

lihans @ 2024-07-27 12:10:44

#include<bits/stdc++.h>
using namespace std;
int m,n;
char mp[1001][1001];
int dx[6]={0,0,0,-1,1};
int dy[6]={0,-1,1,0,0};
void vis(int x,int y)
{
    mp[x][y]='#';
}
bool dfs(int x,int y)
{
    if(x==n&&y==m) return true;
    if(mp[x+dx[1]][y+dy[1]]=='#'&&mp[x+dx[2]][y+dy[2]]=='#'&&mp[x+dx[3]][y+dy[3]]=='#'&&mp[x+dx[4]][y+dy[4]]=='#')
        return false;
    for(int i=1;i<=4;i++)
    {
        if(mp[x+dx[i]][y+dy[i]]=='.')
        {
            vis(x+dx[i],y+dy[i]);
            dfs(x+dx[i],y+dy[i]);
        }
    }
}
int main()
{
    memset(mp,'#',sizeof(mp));
    cin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        for(int j=1;j<=n;j++)
        {
            cin>>mp[i][j];
        }
    }
    if(dfs(1,1))
    {
        cout<<"Yes";
    }
    else
    {
        cout<<"No";
    }
    return 0;
}

by DreamInk @ 2024-07-27 12:25:14

@lihans 你只要不开O2,就不会RE啦

by Diamond_ZuanShi @ 2024-07-27 18:37:41

你可以用数组标记，这样比函数标记要方便，而且你是dfs，好像没回溯嘿？

by Ahws_rwhy @ 2024-08-01 10:06:58

@lihans

#include <iostream>
#include <vector>
#include <queue>
using namespace std;
bool bfs(int n, int m, vector<vector<char>>& maze) {
    vector<vector<bool>> visited(n, vector<bool>(m, false));
    queue<pair<int, int>> q;
    q.push({0, 0});
    visited[0][0] = true;
    while (!q.empty()) {
        int x = q.front().first;
        int y = q.front().second;
        q.pop();

        if (x == n-1 && y == m-1) {
            return true; 
        }
        int dx[4] = {-1, 1, 0, 0};
        int dy[4] = {0, 0, -1, 1};
        for (int i = 0; i < 4; i++) {
            int nx = x + dx[i];
            int ny = y + dy[i];
            if (nx >= 0 && nx < n && ny >= 0 && ny < m && !visited[nx][ny] && maze[nx][ny] == '.') {
                q.push({nx, ny});
                visited[nx][ny] = true;
            }
        }
    }
    return false; 
}
int main() {
    int n, m;
    cin >> n >> m;
    vector<vector<char>> maze(n, vector<char>(m));
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cin >> maze[i][j];
        }
    }
    bool result = bfs(n, m, maze);
    if (result) {
        cout << "Yes" << endl;
    } else {
        cout << "No" << endl;
    }
    return 0;
}

by Unknown_Jun @ 2024-08-09 21:40:01

21行后面还要跟一个回溯

mp[x+dx[i]][y+dy[i]]='.';

@lihans