poj 1753 Flip Game

题意和2965差不多，思路也是一样的：链接：2965

代码：

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;
int s[16] =
{
    0xc800,0xe400,0x7200,0x3100,
    0x8c80,0x4e40,0x2720,0x1310,
    0x08c8,0x04c4,0x0272,0x0131,
    0x008c,0x004e,0x0027,0x0013
};
int result = 17;
int tt = 0;
int num = 0;
void search(int d,int step)
{
    if(step >= 17 )
    return ;
    if(d >= 16)
    {
        if((num == tt || num == 0)&&step < result)
        result = step;
        return ;
    }
    num = num^s[d];
    search(d+1,step+1);
    num = num^s[d];
    search(d+1,step);

}
int main()
{
    char a;
    for(int i = 1; i <= 16 ;++i)
    {
        a=getchar();
        if('\n' == a)
        i--;
        else
        {
            num = num <<1;
            if('b' == a)
            num++;
        }
    }
    for(int i = 1; i <= 16; ++i)
    tt = (tt<<1)^1;
    search(0,0);
    if(result > 16)
    printf("Impossible\n");
    else
    printf("%d\n",result);
    return 0;
}