十四届蓝桥杯第三次模拟赛问题

Question

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

const int N = 35, M = 65;

int n = 30, m = 60;
char g[N][M];

int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};

int dfs(int x, int y) {
    int cnt = 1;
    g[x][y] = '0';
    
    for(int d = 0; d < 4; d ++) {
        int a = x + dx[d], b = y + dy[d];
        if(a <= n && a >= 1 && b <= m && b >= 1 && g[a][b] == '1') {
            cnt += dfs(a, b);
        }
    }
    
    return cnt;
}

int main() {
    
    int res = 0;
    for(int i = 1; i <= n; i ++)
        for(int j = 1; j <= m; j ++)
            cin >> g[i][j];
            
    for(int i = 1; i <= n; i ++)
        for(int j = 1; j <= m; j ++)
            if(g[i][j] == '1')
                res = max(res, dfs(i, j));

    cout << res << "\n";
    return 0;
    
}

想问一下，函数dfs的作用是什么，为什么要定义N和M为35，65
代码第十行和第12行也不懂

Answer 1

• 这有个类似的问题, 你可以参考下: https://ask.csdn.net/questions/7530950