hdu2918—IDA*

//不用剪枝，直接的#include<stdio.h>#include<algorithm>#include<string.h>using namespace std;int n,m,t;char str[12];int ans[10];bool fit(int mid[]){    for(int i=1;i<10;i++)    {        if(mid[i]!=i) return 0;    }    return 1;}void swap(int mid[],int a,int b,int c,int d){    int pt=mid[a];    mid[a]=mid[b],mid[b]=mid[c],mid[c]=mid[d];    mid[d]=pt;}void swap(int mid[],int id){    if(id==1) swap(mid,1,2,5,4);    if(id==2) swap(mid,2,3,6,5);    if(id==3) swap(mid,4,5,8,7);    if(id==4) swap(mid,5,6,9,8);    if(id==5) swap(mid,8,9,6,5);    if(id==6) swap(mid,7,8,5,4);    if(id==7) swap(mid,5,6,3,2);    if(id==8) swap(mid,4,5,2,1);}bool dfs(int mid[],int dep,int fa){    if(fit(mid)) return 1;    if(dep>=m) return 0;    for(int i=1;i<9;i++)    {        swap(mid,i);        if(dfs(mid,dep+1,i)) return 1;        swap(mid,9-i);    }    return 0;}int main(){    int i,j,k,end=1;    while(scanf("%s",str)!=EOF)    {        if(str[0]=='0'&&str[1]=='0') break;        t=str[0]-'0';        for(i=1;i<10;i++) ans[i]=str[i]-'0';        for(m=0;m<=t;m++)        {            if(dfs(ans,0,-1)) break;        }        printf("%d. ",end++);        if(m<=t) printf("%d\n",m);        else puts("-1");    }    return 0;}