POJ1979

搜索过程中使用ans记录搜索步数

#include<iostream>
using namespace std;
const int Max= 22;
 
int row, col, ans;
bool map[Max][Max], vis[Max][Max];
int dr[4] = {0, 1, -1, 0};
int dc[4] = {-1, 0, 0, 1};
 
bool inmap(int r, int c){
    if(r >= 1 && r <= row && c >= 1 && c <= col)
        return  true;
    return  false;
}
 
void dfs(int now_r, int now_c){
    for(int i = 0; i < 4; i ++){
        int r = now_r + dr[i];
        int c = now_c + dc[i];
        if(inmap(r, c) && !vis[r][c] && map[r][c]){
            vis[r][c] = true;  //  dfs的简单变形，直接记录搜过的个数。
            ans ++;
            dfs(r, c);
        }
    }
}
 
int main(){
    int i, j, sta_r, sta_c;
    while(1){
        cin >> col >> row;
        if(row == 0 && col == 0)  break;
        for(i = 1; i <= row; i ++)
            for(j = 1; j <= col; j ++){
                char c;
                cin >> c;
                if(c == '.')  map[i][j] = true;
                else if(c == '#')  map[i][j] = false;
                else{
                    map[i][j] = true;
                    sta_r = i;
                    sta_c = j;
                }
            }
        memset(vis, false, sizeof(vis));
        vis[sta_r][sta_c] = true;
        ans = 1;
        dfs(sta_r, sta_c);
        cout << ans << endl;
    }
    return 0;
}