HDU-4628 Pieces 搜索 | DP

　　题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=4628

　　数据不大，枚举本质。首先对枚举出回文串，然后用DP或者搜索，这里因为层数不多，用bfs比较好，或者用IDA*。。。

 //STATUS:C++_AC_140MS_780KB
 #include <functional>
 #include <algorithm>
 #include <iostream>
 //#include <ext/rope>
 #include <fstream>
 #include <sstream>
 #include <iomanip>
 #include <numeric>
 #include <cstring>
 #include <cassert>
 #include <cstdio>
 #include <string>
 #include <vector>
 #include <bitset>
 #include <queue>
 #include <stack>
 #include <cmath>
 #include <ctime>
 #include <list>
 #include <set>
 #include <map>
 using namespace std;
 //using namespace __gnu_cxx;
 //define
 #define pii pair<int,int>
 #define mem(a,b) memset(a,b,sizeof(a))
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define PI acos(-1.0)
 //typedef
 typedef __int64 LL;
 typedef unsigned __int64 ULL;
 //const
 const int N=(<<)+;
 const int INF=0x3f3f3f3f;
 const int MOD=,STA=;
 const LL LNF=1LL<<;
 const double EPS=1e-;
 const double OO=1e15;
 const int dx[]={-,,,};
 const int dy[]={,,,-};
 const int day[]={,,,,,,,,,,,,};
 //Daily Use ...
 inline int sign(double x){return (x>EPS)-(x<-EPS);}
 template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;}
 template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;}
 template<class T> inline T lcm(T a,T b,T d){return a/d*b;}
 template<class T> inline T Min(T a,T b){return a<b?a:b;}
 template<class T> inline T Max(T a,T b){return a>b?a:b;}
 template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);}
 template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);}
 template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));}
 template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));}
 //End

 char s[];
 int sta[N],d[N],t[];
 int T,len,k,up;

 bool check(int status)
 {
     int i,j;
     for(i=j=;status;i++,status>>=)
         if(status&)t[j++]=i;
     for(i=;i<(j>>);i++)
         if(s[t[i]]!=s[t[j-i-]])return false;
     return true;
 }

 void getsta()
 {
     int i;
     up=(<<(len=strlen(s)))-;
     k=;
     for(i=;i<=up;i++)
         if(check(i))sta[k++]=i;
 }

 int bfs()
 {
     int i,u,v;
     queue<int> q;
     q.push();
     mem(d,-);d[]=;
     while(!q.empty()){
         u=q.front();q.pop();
         for(i=;i<k;i++){
             v=sta[i];
             if((u&v)== && d[u|v]==-){
                 d[u|v]=d[u]+;
                 q.push(u|v);
                 if((u|v)==up)return d[u|v];
             }
         }
     }
     return -;
 }

 int main()
 {
   //  freopen("in.txt","r",stdin);
     int i,j;
     scanf("%d",&T);
     while(T--)
     {
         scanf("%s",s);
         getsta();
         printf("%d\n",bfs());
     }
     return ;
 }