csuoj 你经历过绝望吗？两次！ bfs + 优先队列

Description

4月16日，日本熊本地区强震后，受灾严重的阿苏市一养猪场倒塌，幸运的是，猪圈里很多头猪依然坚强存活。当地15名消防员耗时一天解救围困的“猪坚强”。不过与在废墟中靠吃木炭饮雨水存活36天的中国汶川“猪坚强”相比，熊本的猪可没那么幸运，因为它们最终还是没能逃过被送往屠宰场的命运。

我们假设“猪坚强”被困在一个N*M的废墟中，其中“@”表示“猪坚强”的位置，“.”表示可以直接通过的空地，“#”表示不能拆毁的障碍物，“*”表示可以拆毁的障碍物，那么请问消防员至少要拆毁多少个障碍物，才能从废墟中救出“猪坚强”送往屠宰场？（当“猪坚强”通过空地或被拆毁的障碍物移动到废墟边缘时，视作被救出废墟）

Input

多组数据，第一行有一个整数T，表示有T组数据。（T<=100）

以下每组数据第一行有两个整数N和M。(1<=N,M<=100)

接着N行，每行有一个长度为M的字符串。

Output

一个整数，为最少拆毁的障碍物数量,如果不能逃离废墟，输出-1。

Sample Input

3
3 3
###
#@*
***
3 4
####
#@.*
**.*
3 3
.#.
#@#
.#.

Sample Output

1
0
-1

代码：

#include<iostream>
#include<queue>
using namespace std;
struct Node{
    int x;
    int y;
    int z;
};

struct cmp{
    bool operator()(Node a,Node b){
        return a.z > b.z;
    }
};

char ch[100][101];

int main(){
    int t;
    cin  >> t;
    while(t--){
        int n,m;
        cin >> n >> m;
        for(int i = 0;i < n;i++) cin >> ch[i];
        int a,b;
        a = -1;
        for(int i = 0;i < n;i++){
            for(int j = 0;j < m;j++){
                if(ch[i][j] == '@'){
                    a = i;
                    b = j;
                    break;
                }
            }
            if(a != - 1) break;
        }
        priority_queue<Node,vector<Node>,cmp> q;
        int ans = -1;
        struct Node *node = new struct Node;
        node->x = a;
        node->y = b;
        node->z = 0;
        q.push(*node);
        ch[node->x][node->y] = '#';
        bool flag = false;
        while(!q.empty()){
            struct Node *now = new struct Node;
            *now = q.top();
            q.pop();
//            cout << "now " << now->x << "  " << now->y << "  " << now->z << endl;
            if(now->x == 0 || now->x == n - 1 || now->y == 0 || now->y == m - 1){
                ans = now->z;
                break;
            }
            else{
                if(now->y - 1 >= 0){
                    if(ch[now->x][now->y - 1] == '.'){
                        struct Node *temp = new struct Node;
                        temp->x = now->x;
                        temp->y = now->y - 1;
                        temp->z = now->z;
                        q.push(*temp);
//                        cout << "push " << temp->x << "  " << temp->y << "  " << temp->z << endl;
                        ch[now->x][now->y - 1] = '#';
                    }
                    else if(ch[now->x][now->y - 1] == '*'){
                        struct Node *temp = new struct Node;
                        temp->x = now->x;
                        temp->y = now->y - 1;
                        temp->z = now->z + 1;
                        q.push(*temp);
//                        cout << "push " << temp->x << "  " << temp->y << "  " << temp->z << endl;
                        ch[now->x][now->y - 1] = '#';
                    }
                }
                if(now->y + 1 <= m - 1){
                    if(ch[now->x][now->y + 1] == '.'){
                        struct Node *temp = new struct Node;
                        temp->x = now->x;
                        temp->y = now->y + 1;
                        temp->z = now->z;
                        q.push(*temp);
//                        cout << "push " << temp->x << "  " << temp->y << "  " << temp->z << endl;
                        ch[now->x][now->y + 1] = '#';
                    }
                    else if(ch[now->x][now->y + 1] == '*'){
                        struct Node *temp = new struct Node;
                        temp->x = now->x;
                        temp->y = now->y + 1;
                        temp->z = now->z + 1;
                        q.push(*temp);
//                        cout << "push " << temp->x << "  " << temp->y << "  " << temp->z << endl;
                        ch[now->x][now->y + 1] = '#';
                    }
                }
                if(now->x - 1 >= 0){
                    if(ch[now->x - 1][now->y] == '.'){
                        struct Node *temp = new struct Node;
                        temp->x = now->x - 1;
                        temp->y = now->y;
                        temp->z = now->z;
                        q.push(*temp);
//                        cout << "push " << temp->x << "  " << temp->y << "  " << temp->z << endl;
                        ch[now->x - 1][now->y] = '#';
                    }
                    else if(ch[now->x - 1][now->y] == '*'){
                        struct Node *temp = new struct Node;
                        temp->x = now->x - 1;
                        temp->y = now->y;
                        temp->z = now->z + 1;
                        q.push(*temp);
//                        cout << "push " << temp->x << "  " << temp->y << "  " << temp->z << endl;
                        ch[now->x - 1][now->y] = '#';
                    }
                }
                if(now->x + 1 <= n - 1){
                    if(ch[now->x + 1][now->y] == '.'){
                        struct Node *temp = new struct Node;
                        temp->x = now->x + 1;
                        temp->y = now->y;
                        temp->z = now->z;
                        q.push(*temp);
//                        cout << "push " << temp->x << "  " << temp->y << "  " << temp->z << endl;
                        ch[now->x + 1][now->y] = '#';
                    }
                    else if(ch[now->x + 1][now->y] == '*'){
                        struct Node *temp = new struct Node;
                        temp->x = now->x + 1;
                        temp->y = now->y;
                        temp->z = now->z + 1;
                        q.push(*temp);
//                        cout << "push " << temp->x << "  " << temp->y << "  " << temp->z << endl;
                        ch[now->x + 1][now->y] = '#';
                    }
                }
            }
        }
        cout << ans << endl;
    }
    return 0;
}