POJ 2965

WA 11 了  居然是没有去掉注释。。。。ORZ自己了，有自己一个响亮的耳光。

没什么难度，状态转移，BFS，然后打出答案就行了，记得有个点会被change2次，在变一次就行了

/***
BFS

MDK

2965

Accepted

3620K

782MS

G++

2590B

2011-11-06 20:14:26

*/

struct node {
    int sta;
    int step;
    int prenode;
    int x,y;
    node(int a=0,int b=0,int c=0,int d=0,int e=0)
    :sta(a),step(b),prenode(c),x(d),y(e){}
};
char mat[5][5];
int sta,dex;
bool has[MAXN] = {0};
node Q[MAXNT];

int xytoline(int x,int y) {
    return 4 * x + y;
}

int BFS() {
    SET(has,0);
    int front=0,rear=0;

    Q[rear++] = node(sta,0,0);
    node top(0,0);has[sta] = 1;
    while(front != rear)  {
        top = Q[front++];

        if(top.sta == 65535) {
            dex = front - 1;
            return top.step;
        }
        F(i,4) F(j,4) {
            int sta = top.sta;
            FOR(k,4*i,4*i + 3) {
                sta ^= 1 << (k);
            }
            for(int k = 0;k<4;k++) {
                sta ^= 1 << (xytoline(k,j));
            }
            sta ^= 1<<(xytoline(i,j));
            if(!has[sta]) {
                Q[rear ++] = node(sta,top.step + 1,front -1,i,j);
                has[sta] = 1;
            }
        }
    }
    return -1;
}

void print(int x) {
    if(Q[x].prenode) print(Q[x].prenode);
    printf("%d %d\n",Q[x].x +1,Q[x].y+1);
}

int main () {
    FOPEN

    SET(mat,'\0');

    while(~SCFS(mat[0])) {
        SCFS(mat[1]);SCFS(mat[2]);SCFS(mat[3]);
        sta = 0;
        F(i,4) F(j,4) {
            if(mat[i][j] == '-') {
                sta |= 1 << (xytoline(i,j));
            }
        }

        int ans = BFS();
        if(ans != -1) {
            PCFLN(ans);
            if(dex)print(dex);
            else puts("");
        }
        SET(mat,'\0');
    }
}