POJ 1753 Flip Game 状态压缩 枚举

POJ 1753

枚举,压缩状态,bfs~

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <queue>
using namespace std;
int pow2[17]={1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,65536};
int change[16]={51200,58368,29184,12544,
                35968,20032,10016,4880,
                2248,1252,626,305,
                140,78,39,19};
int tar1,tar2;
int hash[131080];
struct node
{
    int dep;
    int n;
};
queue<node> q;
int main()
{
    int ori,ite,i,t;
    char tc;
    node temp,tn;
    ite=15;
    ori=0;
    tar1=0;
    tar2=65535;
    memset(hash,0,sizeof(hash));
    while (scanf("%c",&tc) != EOF)
    {
        if (tc == 'b')
        {
            ori+=pow2[ite];
            ite--;
        }
        else if (tc == 'w')
        {
            ite--;
        }
    }
        hash[ori]=1;
        temp.dep=0;
        temp.n=ori;
        if (ori == tar1 || ori == tar2)
        {
            printf("0\n");
            return 0;
        }
        while (!q.empty())
            q.pop();
        q.push(temp);
        while (!q.empty())
        {
            temp=q.front();
            q.pop();
            for (i=0; i<16; i++)
            {
                t=temp.n^change[i];
                if (t == tar1 || t == tar2)
                {
                    printf("%d\n",temp.dep+1);
                    return 0;
                }
                if (hash[t] == 1)
                    continue;
                tn.n=t;
                hash[t]=1;
                tn.dep=temp.dep+1;
                q.push(tn);
            }
        }
        printf("Impossible\n");
        return 0;
}


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