AtCoder Beginner Contest 311 D（dfs/bfs）

 

 

 

代码

#include <iostream>
#include <bits/stdc++.h>
#define ull unsigned long long
 
using namespace std;
 
int G[200][200];
int visited[200][200];
 
int res = 1;
 
void dfs(int x, int y) {
    int step = 0;
    int inc = 0;
    int i = x;
    while(!G[i+1][y]) {
        i++;
        if(!visited[i][y]) {
            inc++;
            visited[i][y] = 1;
        }
    }
    if(inc) {
        res += inc;
        dfs(i, y);
    }
    i = x;
    inc = 0;
    while(!G[i-1][y]) {
        i--;
        if(!visited[i][y]) {
            inc++;
            visited[i][y] = 1;
        }
    }
    if(inc) {
        res += inc;
        dfs(i, y);
    }
    i = y;
    inc = 0;
    while(!G[x][i+1]) {
        i++;
        if(!visited[x][i]) {
            inc++;
            visited[x][i] = 1;
        }
    }
    if(inc) {
        res += inc;
        dfs(x, i);
    }
    i = y;
    inc = 0;
    while(!G[x][i-1]) {
        i--;
        if(!visited[x][i]) {
            inc++;
            visited[x][i] = 1;
        }
    }
    if(inc) {
        res += inc;
        dfs(x, i);
    }
}
 
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n, m;
    cin >> n >> m;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            char c;
            cin >> c;
            if(c == '#') {
                G[i][j] = 1;
            }
        }
    }
    visited[1][1] = 1;
    dfs(1, 1);
    cout << res << '\n';
    return 0;
}