WA：csu1108 Flip Game

在POJ上提交用的是枚举，刚学了bfs

各种混乱，WA了

# include <stdio.h>
# include <string.h>
 
# define MAX 65536
 
# define INDEX(i) ((i)>>3)
# define OFFSET(i) ((i)%8)
 
# define GET_BIT(i) (vis[INDEX(i)]>>OFFSET(i) & 0x1)
# define SET_BIT(i) (vis[INDEX(i)] |= 0X1<<OFFSET(i))
 
char vis[INDEX(MAX)+1];
unsigned short Q[MAX+20];
unsigned short f[] = {0x13,0x27,0x4e,0x8c,0x131,0x272,0x4e4,0x8c8,
                      0x1310,0x2720,0x4e40,0x8c80,0x3100,0x7200,0xe400,0xc800
                     };
 
int flip(unsigned short start, unsigned short x)
{
    int i;
 
    for (i = 0; i < 16; ++i)
        if ((x>>i) & 0x1) start ^= f[i];
    if (0==start || 0xff==start) return 1;
    return 0;
}
int bfs(unsigned short start)
{
    unsigned short x;
    int i, front, rear;
 
    front = 0;
    rear = 1;
    SET_BIT(0);
    while (rear!=front)
    {
        x = Q[front++];
        //printf("front = %d, rear = %d, 0x%x\n", front, rear, x);
        if (flip(start, x)) return x;
        else for (i = 0; i < 16; ++i)
                if ((x>>i) & 0x1) continue;
                else if(!GET_BIT(x+(0x1<<i)))
                    {Q[rear++] = x+(0x1<<i);
                     SET_BIT(x+(0x1<<i));
                    }
    }
    return -1;
}
int main()
{
    unsigned short start, i;
    int chg, ans;
    char ch;
 
    //freopen("in.txt", "r", stdin);
    //freopen("out.txt", "w", stdout);
 
    start = i = 0;
    while (i < 16)
    {
        ch = getchar();
        if (ch == 'b')
        {
            start += 0x1<<i;
            //printf("1");
            ++i;
        }
        else if (ch == 'w')
        {
            ++i;
            //printf("0");
        }
    }
    //printf("\n");
    ans = 0;
    chg = bfs(start);
    if (chg == -1) printf("Impossible\n");
    else
    {
        for (i = 0; i < 16; ++i)
            if (chg>>i & 0x1) ++ans;
        printf("%d\n", ans);
    }
    return 0;
}