First Missing Positive

不好想，用桶排序解决。

 int findMissingPostive(int A[], int n)
      {
          bucket_sort(A, n);
          for (int i = ; i < n; i++)
              if (A[i] != i + )
                  return i + ;

          return n + ;

      }

      void bucket_sort(int A[], int n)
      {
          for (int i = ; i < n; i++)
          {
              while (A[i] != i + )
              {
                  if (A[i]<= || A[i]>n || A[i] == A[A[i] - ])
                      break;

                  swap(A[i], A[A[i] - ]);
              }
          }
      }