poj 3279(开关问题)(待完成)

传送门:Problem 3279

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
#define mem(a,b) (memset(a,b,sizeof a))
const int maxn=15+50;

int m,n;
int tile[maxn][maxn];
int f[maxn][maxn];
int res[maxn][maxn];
int times;
bool isWhite(int x,int y)
{
    return (f[x][y]+f[x-1][y]+f[x][y+1]+f[x][y-1]+tile[x][y])%2;
}
void Solve()
{
    times=-1;
    mem(res,0);
    for(int i=0;i < (1<<n);++i)
    {
        mem(f,0);
        int index=n;
        int num=i;
        /*
        for(int j=1;j <= n;++j)
            f[1][j]= (i>>(j-1)&1);
        */
        do
        {
            f[1][index--]=num%2;
            num >>= 1;
        }while(num != 0 && index > 0);
        for(int j=2;j <= m;++j)
            for(int k=1;k <= n;++k)
                if(isWhite(j-1,k) != 0)
                    f[j][k]=1;

        bool flag=false;
        for(int k=1;k <= n;++k)
            if(isWhite(m,k) != 0)
                flag=true;
        if(!flag)
        {
            int cnt=0;
            for(int j=1;j <= m;++j)
                for(int k=1;k <= n;++k)
                    cnt += f[j][k];
            if(times == -1 || times > cnt)
            {
                times=cnt;
                memcpy(res,f,sizeof f);
            }
        }
    }
    if(times == -1)
        printf("IMPOSSIBLE
");
    else
        for(int i=1;i <= m;++i)
            for(int j=1;j <= n;++j)
                printf("%d%c",res[i][j],j == n ? '
':' ');
}
int main()
{
    scanf("%d%d",&m,&n);
    for(int i=1;i <= m;++i)
        for(int j=1;j <= n;++j)
            scanf("%d",&tile[i][j]);
    Solve();
}