[codevs1004]四子连棋

题目←

没什么思维难度的搜索，但比较锻炼思路的清晰程度
外加：
1、x & (1 << j)，x第j位为1，得到的是(1 << j)
2、’||’、’&&’在使用时，对下面的影响一定要想清楚

#include
#include
#include
#include
using namespace std;
const int MAXN = 10 + 5;
struct zt{
    bool first;
    int map[4];
    int x1,y1,x2,y2;
    int step;
}chu;
queue  q;
string s;
bool check(zt u){
    for(int i = 0;i < 4;i ++){
        if(i == u.x1 || i == u.x2)continue;
        bool flag = true;
        for(int j = 0;j < 4;j ++){
            if((bool)(u.map[i] & (1 << j)) != (bool)(u.map[i] & 1)){
                flag = false;
                break;
            }
        }
        if(flag)return true;
    }
    for(int j = 0;j < 4;j ++){
        if(j == u.y1 || j == u.y2)continue;
        bool flag = true;
        for(int i = 0;i < 4;i ++){
            if((bool)(u.map[i] & (1 << j)) != (bool)(u.map[0] & (1 << j))){
                flag = false;
                break;
            }
        }
        if(flag)return true;
    }
    //if(u.x1 == u.y1 || u.x1 + u.y1 == 3)return false;
    //if(u.x2 == u.y2 || u.x2 + u.y2 == 3)return false;
    //一开始这里没想清楚，左对角线上有空格也直接把右对角线过掉了，wa了四个点
    if(u.x1 == u.y1 || u.x2 == u.y2)return false;
    /*if(u.step == 4){
        printf("haha");
        printf("");
    }*/
    int ch = (bool)(u.map[0] & 1);
    bool flag = true;
    for(int i = 1;i < 4;i ++){
        if((bool)(u.map[i] & (1 << i)) != ch){
            flag = false;
            break;
        }
    }
    if(flag)return true;
    if(u.x1 + u.y1 == 3 || u.x2 + u.y2 == 3)return false;
    ch = (bool)(u.map[3] & 1);
    flag = true;
    for(int i = 2;i >= 0;i --){
        if((bool)(u.map[i] & (1 << (3 - i))) != ch){
            flag = false;
            break;
        }
    }
    if(flag)return true;
    return false;
}
int get(zt u,int x,int y){
    return (bool)(u.map[x] & (1 << y));
}
int mu[] = {0,1,-1,0},
    mr[] = {1,0,0,-1};
bool used[16][16][16][16][5][5][5][5][2];
bool can(int x,int y){
    if(x < 0 || y < 0)return false;
    if(x > 3 || y > 3)return false;
    return true;
}
bool in(zt u){
    return used[u.map[0]][u.map[1]][u.map[2]][u.map[3]][u.x1][u.y1][u.x2][u.y2][u.first];
}
void add(zt u){
    used[u.map[0]][u.map[1]][u.map[2]][u.map[3]][u.x1][u.y1][u.x2][u.y2][u.first] = true;
}
int ans,x2,y2,x1,y1;
int main(){
    chu.x1 = -1;
    for(int i = 0;i < 4;i ++){
        cin >> s;
        for(int j = 0;j < 4;j ++){
            if(s[j] == 'B'){
                chu.map[i] += (1 << j);
            }
            if(s[j] == 'O' && chu.x1 == -1){
                chu.x1 = i;
                chu.y1 = j;
            }
            else if(s[j] == 'O'){
                chu.x2 = i;
                chu.y2 = j;
            }
        }
    }
    chu.first = 0;
    q.push(chu);
    chu.first = 1;
    q.push(chu);
    used[chu.map[0]][chu.map[1]][chu.map[2]][chu.map[3]][chu.x1][chu.y1][chu.x2][chu.y2][0] = true;
    used[chu.map[0]][chu.map[1]][chu.map[2]][chu.map[3]][chu.x1][chu.y1][chu.x2][chu.y2][1] = true;
    while(!q.empty()){
        zt u = q.front();
        q.pop();
    //  if(u.map[0] == 5)printf("haha");
        for(int i = 0;i <= 3;i ++){
            int xx = u.x1 + mu[i];
            int yy = u.y1 + mr[i];
            if(can(xx,yy) && ((bool)(u.map[xx] & (1 << yy)) == u.first) && (xx != u.x2 || yy != u.y2)){
                zt tmp = u;
                int tmp1 = get(tmp,xx,yy);
                tmp.map[xx] -= (tmp1 << yy);
                tmp.map[u.x1] += (tmp1 << u.y1);
                tmp.x1 = xx;
                tmp.y1 = yy;
                tmp.first ^= 1;
                if(!in(tmp)){
                    add(tmp);
                    tmp.step ++;
                    if(check(tmp)){/*
                        for(int i = 0;i < 4;i ++){
                            printf("%d\n",tmp.map[i]);
                        }
                        check(tmp);*/
                        printf("%d",tmp.step);
                        return 0;
                    }
                    q.push(tmp);
                }
            }
            xx = u.x2 + mu[i];
            yy = u.y2 + mr[i];
            if(can(xx,yy) && ((bool)(u.map[xx] & (1 << yy)) == u.first) && (xx != u.x1 || yy != u.y1)){
                zt tmp = u;
                int tmp1 = get(tmp,xx,yy);
                tmp.map[xx] -= (tmp1 << yy);
                tmp.map[u.x2] += (tmp1 << u.y2);
                tmp.x2 = xx;
                tmp.y2 = yy;
                tmp.first ^= 1;
                if(!in(tmp)){
                    add(tmp);
                    tmp.step ++;
                    if(check(tmp)){

                        //check(tmp);
                        printf("%d",tmp.step);
                        return 0;
                    }
                    q.push(tmp);
                }
            }
        }
    }
}