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(简单) HDU 2612 Find a way,BFS。

  Description

  Pass a year learning in Hangzhou, yifenfei arrival hometown Ningbo at finally. Leave Ningbo one year, yifenfei have many people to meet. Especially a good friend Merceki.
Yifenfei’s home is at the countryside, but Merceki’s home is in the center of city. So yifenfei made arrangements with Merceki to meet at a KFC. There are many KFC in Ningbo,  they want to choose one that let the total time to it be most smallest.
  Now give you a Ningbo map, Both yifenfei and Merceki can move up, down ,left, right to the adjacent road by cost 11 minutes.

 

  就是求两个人到某一个KFC的最小值,这个题记得以前做的时候被坑惨了,要注意初始化为INF,以及说人的起始位置要表示为可通过。

 

代码如下:

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#include<iostream>#include<cstring>using namespace std;const int INF=1e7;short map1[205][205];int que[40005],las,fir;int ans[205][205];int ans1[205][205];int N,M;int couKFC,Si,Sj,Ei,Ej;bool judge(int x,int y,int (*rem)[205]){    if(x<=0||y<=0||x>N||y>M)        return 0;    if(rem[x][y]!=INF)        return 0;    if(map1[x][y]==0)        return 0;    return 1;}void bfs(int x,int y,int (*rem)[205]){    las=fir=0;    int cou=0;    int temp,t1,t2;    que[las++]=x*1000+y;    rem[x][y]=0;    while(las-fir)    {        temp=que[fir++];        t1=temp/1000;        t2=temp%1000;        temp=rem[t1][t2];        if(map1[t1][t2]==2)            ++cou;        if(cou>=couKFC)            return;        --t1;        if(judge(t1,t2,rem))        {            rem[t1][t2]=temp+1;            que[las++]=t1*1000+t2;        }            t1+=2;        if(judge(t1,t2,rem))        {            rem[t1][t2]=temp+1;            que[las++]=t1*1000+t2;        }            --t1;        --t2;        if(judge(t1,t2,rem))        {            rem[t1][t2]=temp+1;            que[las++]=t1*1000+t2;        }            t2+=2;        if(judge(t1,t2,rem))        {            rem[t1][t2]=temp+1;            que[las++]=t1*1000+t2;        }    }}int slove(){    bfs(Si,Sj,ans);    bfs(Ei,Ej,ans1);    int minn=INF;    for(int i=1;i<=N;++i)        for(int j=1;j<=M;++j)            if(map1[i][j]==2)                if(minn>ans[i][j]+ans1[i][j])                    minn=ans[i][j]+ans1[i][j];    return minn*11;}int main(){    ios::sync_with_stdio(false);    char c;    while(cin>>N>>M)    {        couKFC=0;        for(int i=1;i<=N;++i)            for(int j=1;j<=M;++j)            {                cin>>c;                ans[i][j]=ans1[i][j]=INF;                switch(c)                {                    case Y:                        map1[i][j]=1;                        Si=i;                        Sj=j;                        break;                    case M:                        map1[i][j]=1;                        Ei=i;                        Ej=j;                        break;                    case .:                        map1[i][j]=1;                        break;                    case #:                        map1[i][j]=0;                        break;                    case @:                        map1[i][j]=2;                        ++couKFC;                        break;                }            }        cout<<slove()<<endl;    }    return 0;}
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(简单) HDU 2612 Find a way,BFS。