计算整数数组中的重复元素

字典（Java中的HashMap）可以轻松解决此类问题。

  // The solution itself   HashMap<Integer, Integer> repetitions = new HashMap<Integer, Integer>();  for (int i = 0; i < crr_array.length; ++i) {      int item = crr_array[i];      if (repetitions.containsKey(item))          repetitions.put(item, repetitions.get(item) + 1);      else          repetitions.put(item, 1);  }  // Now let's print the repetitions out  StringBuilder sb = new StringBuilder();  int overAllCount = 0;  for (Map.Entry<Integer, Integer> e : repetitions.entrySet()) {      if (e.getValue() > 1) {          overAllCount += 1;          sb.append("n");          sb.append(e.getKey());          sb.append(": ");          sb.append(e.getValue());          sb.append(" times");      }  }  if (overAllCount > 0) {      sb.insert(0, " repeated numbers:");      sb.insert(0, overAllCount);      sb.insert(0, "There are ");  }  System.out.print(sb.toString());