HDU1226 BFS

题意：给定n，m，c 和 k个数

求最小的一个数（这个数是c进制，且是n的倍数）

一共5000个状态，bfs

不会写DFS啊。。。。

不过看了别人的BFS后还是有种恍然大悟的感觉。。。。

View Code

  1 #include<stdio.h>

  2 #include<stdlib.h>

  3 #include<string>

  4 #include<algorithm>

  5 #include<math.h>

  6 #include<iostream>

  7 #include<queue>

  8 using namespace std;

  9 const int maxn = 24;

 10 const int maxm = 5105;

 11 const int inf = 99999999;

 12 int n,m,c;

 13 int a[ maxn ];

 14 int vis[ maxm ];

 15 int flag;

 16 struct node{

 17     string ans;

 18     int mod;

 19 };

 20 string res;

 21 queue<node>q;

 22 void init2(){

 23     while( !q.empty() )

 24         q.pop();

 25 }

 26 void init1(){

 27     memset( a,0,sizeof( a ));

 28     memset( vis,0,sizeof( vis ));

 29     flag=-1;

 30     res.clear();

 31 }

 32 void bfs(){

 33     init2();

 34     node now,next;

 35     for( int i=1;i<16;i++ ){

 36         if( a[i] ){

 37             vis[ i%n ]=1;

 38             if( i>=0&&i<=9 ){

 39                 now.ans="";

 40                 now.ans=(i+'0');

 41                 now.mod=i%n;

 42                 q.push( now );

 43             }

 44             else{

 45                 now.ans="";

 46                 now.ans=(i+'A'-10);

 47                 now.mod=i%n;

 48                 q.push( now );

 49             }

 50         }

 51     }//the init

 52     while( !q.empty() ){

 53         now=q.front(),q.pop();

 54         if( flag==1&&now.ans.size()>res.size() )

 55             continue;

 56         if( now.mod==0 ){

 57             if( flag==-1 ){

 58                 flag=1;

 59                 res=now.ans;

 60             }

 61             else{

 62                 if( now.ans.size()<res.size() ){

 63                     res=now.ans;

 64                 }

 65                 else if( now.ans.size()==res.size()&&res>now.ans ){

 66                     res=now.ans;

 67                 }

 68             }

 69         }

 70         for( int i=0;i<16;i++ ){

 71             if( a[i] ){

 72                 if( i<10 ){

 73                     next=now;

 74                     next.ans+=( i+'0' );

 75                     next.mod=(now.mod*c+i)%n;

 76                     if( ( next.ans.size()<=500&&vis[ next.mod ]==0 )||( next.mod==0 ) ){

 77                         vis[ next.mod ]=1;

 78                         q.push( next );

 79                     }

 80                 }

 81                 else{

 82                     next=now;

 83                     next.ans+=(i+'A'-10);

 84                     next.mod=(now.mod*c+i)%n;

 85                     if( ( next.ans.size()<=500&&vis[ next.mod ]==0 )||( next.mod==0 ) ){

 86                         vis[ next.mod ]=1;

 87                         q.push( next );

 88                     }

 89                 }

 90             }

 91         }

 92     }

 93 }

 94 

 95 int main(){

 96     int ca;

 97     scanf("%d",&ca);

 98     while( ca-- ){

 99         scanf("%d%d%d",&n,&c,&m);

100         init1();

101         char ch[ 4 ];

102         for( int i=0;i<m;i++ ){

103             scanf("%s",ch);

104             if( ch[0]>='0'&&ch[0]<='9' )

105                 a[ ch[0]-'0' ]=1;

106             else

107                 a[ ch[0]-'A'+10 ]=1;

108         }

109          if(n==0){  

110            // cout<<0<<endl;  

111             if(a[0]==1)  

112                 cout<<0<<endl;  

113             else  

114                 cout<<"give me the bomb please"<<endl;  

115             continue;  

116         }  

117         bfs();

118         if( flag==-1 )

119             printf("give me the bomb please\n");

120         else

121             cout<<res<<endl;

122     }

123     return 0;

124 }