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   | #include<cstdio> #include<cstring> using namespace std; const int M = 1000003; int x[4] = { -1, 1, 0, 0}, y[4] = {0, 0, -1, 1}; int dis[M], h[M], s[M][9], e[9];
  int aton(int a[]) {     int t = 0;     for(int i = 0; i < 9; ++i)         t = t * 10 + a[i];     return t; }
  int search_hash(int a[]) {     int t = aton(a), p = t % M;     while(h[p])     {         if(h[p] == t) return p;         ++p;         if(p >= M) p = 0;     }     return p; }
  int bfs() {     memset(h, 0, sizeof(h));     int fro = 1, rear = 2, r, c, k = 0, p;     int t[9], tmp, cur, nr, nc, nk;
      while(fro < rear)     {         memcpy(t, s[fro], sizeof(t));         cur = search_hash(t);         if(memcmp(t, e, sizeof(t)) == 0) return dis[cur];         for(k = 0; t[k];) ++k;         r = k / 3, c = k % 3;         for(int i = 0; i < 4; ++i)         {             memcpy(t, s[fro], sizeof(t));             nr = r + x[i], nc = c + y[i], nk = nr * 3 + nc;             if(nr < 0 || nr > 2 || nc < 0 || nc > 2) continue;             tmp = t[nk];             t[nk] = 0;             t[k] = tmp;             p = search_hash(t);             if(h[p] == 0)             {                 h[p] = aton(t);                 dis[p] = dis[cur] + 1;                 memcpy(s[rear], t, sizeof(t));                 ++rear;             }         }         ++fro;     }     return -1; }
  int main() {     while(~scanf("%d", &s[1][0]))     {         memset(dis, 0, sizeof(dis));         for(int i = 1; i < 9; ++i)             scanf("%d", &s[1][i]);         for(int i = 0; i < 9; ++i)             scanf("%d", &e[i]);         h[aton(s[1]) % M] = aton(s[1]);         int ans = bfs();         if(ans != -1)             printf("%d\n", ans);         else  printf("No solution\n");     }     return 0; }
 
 
 
 
 
 
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