hdu 1401

Solitaire

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 3077    Accepted Submission(s): 954

Problem Description

Solitaire is a game played on a chessboard 8x8. The rows and columns of the chessboard are numbered from 1 to 8, from the top to the bottom and from left to right respectively.

There are four identical pieces on the board. In one move it is allowed to:

> move a piece to an empty neighboring field (up, down, left or right),

> jump over one neighboring piece to an empty field (up, down, left or right).

There are 4 moves allowed for each piece in the configuration shown above. As an example let's consider a piece placed in the row 4, column 4. It can be moved one row up, two rows down, one column left or two columns right.

Write a program that:

> reads two chessboard configurations from the standard input,

> verifies whether the second one is reachable from the first one in at most 8 moves,

> writes the result to the standard output.

Input

Each of two input lines contains 8 integers a1, a2, ..., a8 separated by single spaces and describes one configuration of pieces on the chessboard. Integers a2j-1 and a2j (1 <= j <= 4) describe the position of one piece - the row number and the column number respectively. Process to the end of file.

Output

The output should contain one word for each test case - YES if a configuration described in the second input line is reachable from the configuration described in the first input line in at most 8 moves, or one word NO otherwise.

Sample Input

4 4 4 5 5 4 6 5

2 4 3 3 3 6 4 6

Sample Output

YES

Source

Southwestern Europe 2002

Recommend

四个点的哈希，由于这四个点没有什么区分，哈希的时候注意一下。

由于的用set哈希，用*10的方法。所以要先排序。很容易理解的。

bfs的代码，有点意思。

 /**
 4 4 4 5 5 4 6 5
 2 4 3 3 3 6 4 6

 **/

 #include<iostream>
 #include<stdio.h>
 #include<cstring>
 #include<cstdlib>
 #include<queue>
 #include<algorithm>
 #include<set>
 using namespace std;

 struct node
 {
     int x[];
     int y[];
 };
 struct node start,end1;

 queue<node>Q[];
 set<int>hxl[];
 bool flag;
 int map1[][]={{,},{,},{-,},{,-}};

 bool fun(node &t,int i)
 {
     int j;
     if(t.x[i]>=&&t.x[i]<=  &&  t.y[i]>=&&t.y[i]<=)
     {
         for(j=;j<;j++)
         {
             if(j==i)continue;
             if(t.x[i]==t.x[j] && t.y[i]==t.y[j]) return true;
         }
         return false;
     }
     return true;
 }
 void pai(node &t)
 {
    int i,j,x;
    for(i=;i<; i++)
    {
       x=i;
       for(j=i+;j<; j++)
        if(t.x[x]>t.x[j])
          x=j;
        else if(t.x[x]==t.x[j]  &&  t.y[x]>t.y[j])
          x=j;
       swap(t.x[i],t.x[x]);
       swap(t.y[i],t.y[x]);
    }

 }
 int serch(node &t)
 {
     int i,sum=;
     for(i=;i<;i++)
         sum=sum*+t.x[i]*+t.y[i];
     return sum;
 }
 void bfs(int x)
 {
     int i,j,size1,k;
     node cur,t;
     size1=Q[x].size();
     while(size1--)
     {
         cur=Q[x].front();
         Q[x].pop();
         for(i=;i<;i++)/** every four point  **/
         {
             for(j=;j<;j++) /** n s w e**/
             {
                 t=cur;
                 t.x[i]=t.x[i]+map1[j][];
                 t.y[i]=t.y[i]+map1[j][];
                 if(fun(t,i)==true)
                 {
                     t.x[i]=t.x[i]+map1[j][];
                     t.y[i]=t.y[i]+map1[j][];
                     if(fun(t,i)==true) continue;
                 }
                 pai(t);
                 k=serch(t);
                 if(hxl[x].count(k)>)continue;
                 if(hxl[x^].count(k)>)
                 {
                     flag=true;
                     return;
                 }
                 hxl[x].insert(k);
                 Q[x].push(t);
             }
         }
     }
 }
 void dbfs()
 {
     int ans=,k;
     pai(start);
     k=serch(start);
     hxl[].insert(k);
     Q[].push(start);

     pai(end1);
     Q[].push(end1);
     k=serch(end1);
     hxl[].insert(k);
     while(true)
     {
         if(Q[].size()<Q[].size())
             bfs();
         else bfs();
         ans++;
         if(ans==)break;
         if(flag==true) return;
     }
 }
 int main()
 {
     int i;
     while(scanf("%d%d",&start.x[],&start.y[])>)
     {
         for(i=;i<;i++)
             scanf("%d%d",&start.x[i],&start.y[i]);
         for(i=;i<;i++)
             scanf("%d%d",&end1.x[i],&end1.y[i]);
         while(!Q[].empty()){
             Q[].pop();
         }
         while(!Q[].empty()){
             Q[].pop();
         }
         hxl[].clear();
         hxl[].clear();
         flag=false;
         dbfs();
         if(flag==true) printf("YES\n");
         else printf("NO\n");
     }
     return ;
 }