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 }
keep moving...