洛谷1468 派对灯

using namespace std;
int n, m, cnt = 0, op[105] = {0};
int res[105], ans[10][105], tot = 0;
int ori[10], b[2][10], c[3], to[10];
void (){
    for(int i = 0; i < tot; ++i)
        ori[i] = i;
    for(int i = n - 1; i >= 0; --i){
        c[0] = c[1] = 0;
        for(int j = 0; j < tot; ++j){
            int curbit = ans[ori[j]][i];
            b[curbit][c[curbit]++] = ori[j];
        }
        c[1] += c[0];
        for(int j = tot - 1; j >= 0; --j){
            int curbit = ans[ori[j]][i];
            to[--c[curbit]] = ori[j];
        }
        for(int j = 0; j < tot; ++j)
            ori[j] = to[j];
    }
}
bool judge(){
    for(int i = 0; i < n; ++i)
        if((op[i] == 1 && res[i] == 0) || (op[i] == -1 && res[i] == 1))
            return false;
    memcpy(ans[tot], res, sizeof(res)), tot++;
    return true;
}
inline void reset(){
    fill(res, res + n, 1);
}
void process(int x){
    if(x == 1){
        for(int i = 0; i < n; ++i)
            res[i] ^= 1;
    }else if(x == 2){
        for(int i = 0; i < n; i += 2)
            res[i] ^= 1;
    }else if(x == 3){
        for(int i = 1; i < n; i += 2)
            res[i] ^= 1;
    }else if(x == 4){
        for(int i = 0; i < n; i += 3)
            res[i] ^= 1;
    }
}
int main(){
    scanf("%d%d", &n, &m);
    int t;
    while(scanf("%d", &t), t > 0)
        op[t - 1] = 1;
    while(scanf("%d", &t), t > 0){
        if(op[t - 1] == 1){
            printf("IMPOSSIBLEn");
            return 0;
        }
        op[t - 1] = -1, cnt++;
    }

    bool flag = false;
    if(m == 0){
        if(cnt > 0) {
            printf("IMPOSSIBLEn");
            return 0;
        }
        else{
            for(int i = 0; i < n; ++i)
                printf("1");
            putchar('n');
            return 0;
        }
    }else if(m & 1){
        reset();
        if(m > 1) flag |= judge();
        process(1), flag |= judge();//1
        process(2), flag |= judge();//3
        process(1), flag |= judge();//2
        reset(), process(4), flag |= judge();//4
        if(m > 1){
            process(2), flag |= judge();//24
            process(1), flag |= judge();//34
            process(2), flag |= judge();//14
        }
    }else{
        reset(), flag |= judge();
        process(1), flag |= judge();//1
        process(2), flag |= judge();//3
        process(4), flag |= judge();//34
        process(1), flag |= judge();//24
        process(3), flag |= judge();//14
        reset(), process(2), flag |= judge();//2
        if(m > 2)
            reset(), process(4), flag |= judge();//4
    }
    if(!flag){
        printf("IMPOSSIBLEn");
        return 0;
    }
    ssort();
    for(int i = 0; i < tot; ++i){
        for(int j = 0; j < n; ++j)
            printf("%d", ans[ori[i]][j]);
        putchar('n');
    }
    return 0;
}