九宫重排（搜索）

#include<bits/stdc++.h>
#include<queue>
#include<bits/stdc++.h>
using namespace std;
int p[15], q[15],t[1000005][15],cnt[1000005],vis[1000005];
int fac[15] = { 1 };
int d[5][5] = { {1,0},{-1,0},{0,1},{0,-1} };
int kt(int *a) {
      int sum = 0,u=0;
      for (int i = 0; i < 8; i++) {
          u = 0;
          for (int j = i + 1; j < 9; j++) {
              if (a[i] > a[j])u++;
          }
          sum += u * fac[8 - i];
      }
      if (vis[sum])return 0;
      else {
          vis[sum] = 1;
          return 1;
      }
}
int bfs() {
       int head = 0, tail = 1;
       memcpy(t[0], p, sizeof(p));
       while (head < tail) {
           int tmp[15];
           memcpy(tmp, t[head], sizeof(t[head]));
           if (memcmp(tmp, q,sizeof(q)) == 0)return head;
           int k;
           for (k = 0; k < 9; k++)if (!tmp[k])break;
           int x = k / 3, y = k % 3;
           for (int i = 0; i < 4; i++) {
               int cx = x + d[i][0], cy = y+d[i][1];
               if (cx < 0 || cy < 0 || cx>2 || cy>2)continue;
               int now = 3 * cx + cy;
               int temp[15];
               memcpy(temp, tmp, sizeof(tmp));
               temp[k] = tmp[now];
               temp[now] = 0;
               if (kt(temp))memcpy(t[tail],temp,sizeof(temp)),cnt[tail++] = cnt[head]+1;
           }
           ++head;
       }
       return -1;
}
int main() {
    char ch;
    //for (int i = 1; i <= 10; i++)cout << fac[i] << endl;
    for (int i = 1; i <= 9; i++)fac[i] = i * fac[i - 1];
    //for (int i = 1; i <= 10; i++)cout << fac[i] << endl;
    for (int i = 0; i < 9; i++) {
        cin >> ch;
        if (ch == ‘.‘)p[i] = 0;
        else p[i] = ch - ‘0‘;
    }
    for (int i = 0; i < 9; i++) {
        cin >> ch;
        if (ch == ‘.‘)q[i] = 0;
        else q[i] = ch - ‘0‘;
    }
    int ans = bfs();
    if (ans == -1)cout << -1 << endl;
    else cout << cnt[ans] << endl;
    return 0;
}