foo.cpp: In function 'void Search(int)':
foo.cpp:55:40: error: 'printf' was not declared in this scope
         for (i = 1; i <= 9; printf("\n"), i ++)
                                        ^
foo.cpp: In function 'int main()':
foo.cpp:78:33: error: 'getchar' was not declared in this scope
     for (i = 1; i <= 9; getchar(), i ++)
                                 ^
foo.cpp:80:33: error: 'memset' was not declared in this scope
     memset(flag, 0, sizeof(flag));
                                 ^
foo.cpp:91:64: warning: operation on 'n' may be undefined [-Wsequence-point]
             a[++ n][(i-1)*9+j] = a[n][81+(i-1)*9+map[i][j]] = 1;
                                                                ^
foo.cpp:97:58: warning: operation on 'n' may be undefined [-Wsequence-point]
               a[++ n][(i-1)*9+j] = a[n][81+(i-1)*9+k] = 1;
                                                          ^
foo.cpp:108:77: warning: operation on 'U[j]' may be undefined [-Wsequence-point]
             top ++, C[top] = j, U[top] = U[j], D[U[j]] = U[j] = top, S[j] ++;
                                                                             ^
foo.cpp:110:71: warning: operation on 'L[first[i]]' may be undefined [-Wsequence-point]
               L[top] = L[first[i]], R[L[first[i]]] = L[first[i]] = top;
                                                                       ^
foo.cpp: In function 'int Get(int, int)':
foo.cpp:16:3: warning: control reaches end of non-void function [-Wreturn-type]
   }
   ^