POJ2286 The Rotation Game

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题目：http://poj.org/problem?id=2286
分析：第一个IDA* 程序。。WA了无数次，原因：判深度超应该放在判合法解之前！
代码：

#include <cstdio>#include <algorithm>#include <cstring>#include <vector>using namespace std;const int Tmax=30,p[9][8]={{0},{0,1,3,7,12,16,21,23},{0,2,4,9,13,18,22,24},{0,11,10,9,8,7,6,5},{0,20,19,18,17,16,15,14},{0,24,22,18,13,9,4,2},{0,23,21,16,12,7,3,1},{0,14,15,16,17,18,19,20},{0,5,6,7,8,9,10,11}};const int cp[9]={0,7,8,9,12,13,16,17,18};int a[Tmax],dep,num[4],z[Tmax]={0,1,1,1,1,3,2,3,2,3,1,3,2,2,3,1,2,2,2,3,1,2,1,3,3};vector<int> ans;bool ok(){    int i;    for(i=2;i<=8;i++)      if(a[cp[i]]!=a[cp[1]]) return false;    return true;}int h(){    int i;    num[1]=num[2]=num[3]=0;    for(i=1;i<=8;i++)      num[a[cp[i]]]++;    return max(num[1],max(num[2],num[3]));}bool dfs(int d,int pre){    if(d>dep) return false;    if(ok()) return true;    if(d+8-h()>dep+1) return false;    int i,tmp,j;    for(i=1;i<=8;i++)    {        if((i==1&&pre==6)||(i==2&&pre==5)||(i==3&&pre==8)||(i==4&&pre==7)||(i==5&&pre==2)||(i==6&&pre==1)||(i==7&&pre==4)||(i==8&&pre==3)) continue;        tmp=a[p[i][1]];        for(j=1;j<=6;j++)          a[p[i][j]]=a[p[i][j+1]];        a[p[i][7]]=tmp;        ans.push_back(i);        if(dfs(d+1,i)) return true;        ans.pop_back();        tmp=a[p[i][7]];        for(j=7;j>=2;j--)          a[p[i][j]]=a[p[i][j-1]];        a[p[i][1]]=tmp;    }    return false;}int main(){    int i;    while(scanf("%d",&a[1])&&a[1]!=0)    {        ans.clear();        for(i=2;i<=24;i++)          scanf("%d",&a[i]);        if(ok())        {            printf("No moves needed\n");            printf("%d\n",a[7]);            continue;        }        dep=1;        while(!dfs(0,-10))           dep++;        for(i=0;i<ans.size();i++)          printf("%c",ans[i]+'A'-1);        printf("\n%d\n",a[7]);    }    return 0;}

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