Find a way (BFS)

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2612

BFS搜索  目标地  并记录下来  之后再判断两段路程之和

代码:

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

 #define INF 0x3f3f3f3f
 #define N 220
 #define M 220
 int n,m;
 char mp[N][M];
 int vis1[N][M],vis2[N][M];
 int ans1[N][M],ans2[N][M];
 int dx[]={,,,-};
 int dy[]={,-,,};

 struct node
 {
     int x,y;
     int t;
 };

 node g1,g2;
 void getMp()
 {
     for(int i=; i<n; i++){
         for(int j=; j<m; j++){
             cin>>mp[i][j];
             if(mp[i][j]=='Y'){
                 g1.x=i;
                 g1.y=j;
                 g1.t=;
                 vis1[i][j]=;
             }
             if(mp[i][j]=='M'){
                 g2.x=i;
                 g2.y=j;
                 g2.t=;
                 vis2[i][j]=;
             }
         }
     }
 }

 void bfs1()
 {
     queue<node> q;
     while(!q.empty())
         q.pop();
     q.push(g1);
     while(!q.empty()){
         node f1;
         f1=q.front();
         q.pop();
         for(int i=; i<; i++){
             node f2;
             f2.x=f1.x+dx[i];
             f2.y=f1.y+dy[i];
             f2.t=f1.t;
             if(<=f2.x&&f2.x<n&&<=f2.y&&f2.y<m&&!vis1[f2.x][f2.y]&&mp[f2.x][f2.y]!='#'){
                 f2.t++;
                 if(mp[f2.x][f2.y]=='@'){
                     ans1[f2.x][f2.y]=f2.t;
                 }
                 vis1[f2.x][f2.y]=;
                 q.push(f2);
             }
         }
     }
 }

 void bfs2()
 {
     queue<node> q;
     while(!q.empty())
         q.pop();
     q.push(g2);
     while(!q.empty()){
         node f1;
         f1=q.front();
         q.pop();
         for(int i=; i<; i++){
             node f2;
             f2.x=f1.x+dx[i];
             f2.y=f1.y+dy[i];
             f2.t=f1.t;
             if(<=f2.x&&f2.x<n&&<=f2.y&&f2.y<m&&!vis2[f2.x][f2.y]&&mp[f2.x][f2.y]!='#'){
                 f2.t++;
                 if(mp[f2.x][f2.y]=='@'){
                     ans2[f2.x][f2.y]=f2.t;
                 }
                 vis2[f2.x][f2.y]=;
                 q.push(f2);
             }
         }
     }
 }

 int main()
 {
     while(~scanf("%d %d",&n,&m)){
         memset(ans1,-,sizeof(ans1));
         memset(ans2,-,sizeof(ans2));
         memset(vis1,,sizeof(vis1));
         memset(vis2,,sizeof(vis2));
         getMp();
         bfs1();
         bfs2();
         int min=INF;
         for(int i=;i<n;i++)
             for(int j=;j<m;j++)
             {
                 if(ans1[i][j]+ans2[i][j]<min&&ans1[i][j]+ans2[i][j]>)
                 {
                     min=ans1[i][j]+ans2[i][j];
                 }
             }
         printf("%d\n",min*);
     }
 }