Borg Maze---poj3026最小生成树+bfs

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<math.h>
#include<algorithm>
#include<queue>
#include<iostream>
using namespace std;

#define N 105
#define INF 0xfffffff
int dir[4][2] = { {1, 0}, {-1, 0}, {0, 1}, {0, -1} };
int D[N][N], n, m, vis[N], used[N][N],b[N][N], dist[N];
char map[N][N];

struct node
{
    int x, y, step;
} a[N];

void bfs(int s, int x, int y)
{
    memset(used, 0, sizeof(used));
    node p,q;
    queue<node>Q;
    p.x = x;
    p.y = y;
    p.step = 0;
    Q.push(p);
    used[x][y] = 1;
    while(Q.size())
    {
        p = Q.front();
        Q.pop();
        if(map[p.x][p.y] >= ‘A‘ && map[p.x][p.y] <= ‘Z‘)
            D[s][ b[p.x][p.y] ] = p.step;
        for(int i=0; i<4; i++)
        {
            q.x = p.x + dir[i][0];
            q.y = p.y + dir[i][1];
            if(q.x<m && q.x>=0 && q.y>=0 && q.y<n && used[q.x][q.y]!=1 && map[q.x][q.y] != ‘#‘)
            {
                used[q.x][q.y] = 1;
                q.step = p.step + 1;
                Q.push(q);
            }
        }
    }
}

int Prim(int cnt)
{
    int ans=0;
    vis[1] = 1;
    for(int i=1; i<=cnt; i++)
        dist[i] = D[1][i];
    for(int i=1; i<=cnt; i++)
    {
        int Min = INF, index = -1;
        for(int j=1; j<=cnt; j++)
            if(vis[j]==0 && Min > dist[j])
            {
                Min = dist[j];
                index = j;
            }
        if(index==-1)break;
        ans += Min;
        vis[index] = 1;
        for(int j=1; j<=cnt; j++)
        {
            if(vis[j] == 0 && dist[j] > D[index][j])
               dist[j] = D[index][j];
        }
    }
    return ans;
}

int main()
{
    int T, ans;
    scanf("%d", &T);
    while(T--)
    {
        memset(a, 0, sizeof(a));
        memset(vis, 0, sizeof(vis));

        memset(map, 0, sizeof(map));
        for(int i=0; i<N; i++)
        {
            dist[i] = INF;
            for(int j=0; j<N; j++)
                D[i][j] = INF;
            D[i][i] = 0;
        }

        int cnt = 1;
        scanf("%d%d ", &n,&m);
        for(int i=0; i<m; i++)
        {
            gets(map[i]);
            for(int j=0; j<n; j++)
            {
                if(map[i][j] <= ‘Z‘ && map[i][j] >= ‘A‘)
                    b[i][j] = cnt, cnt++;
            }
        }
        for(int i=0; i<m; i++)
        {
            for(int j=0; j<n; j++)
            {
                if(map[i][j] <= ‘Z‘ && map[i][j] >= ‘A‘)
                    bfs(b[i][j], i, j);
            }
        }
        ans = Prim(cnt-1);
        printf("%d\n", ans);
    }
    return 0;
}