java 找出數組中僅出現1次的那個數字

Given an array of integers, every element appears three times except for one. Find that single one.

e.g. 數組{1,2,3,1,1,3,2,2,3,54,66,54,54}  中 特殊數字是66，他只出現1次，其他數字出現3次。

    /**
     * Given an array of integers, every element appears three times except for one. Find that single one.
     */
    public static void findSpecialNum() {
        //構造一個符合條件的數組
        //產生diffNum個不同的數字
        int diffNum = 4;
        ArrayList<Integer> list = new ArrayList<>();
        for (int i = 0; i < Integer.MAX_VALUE; i++) {
            int x = (int) (Math.random() * 100);
            if (!list.contains(x)) {
                list.add(x);
            }
            if (list.size() == diffNum) {
                break;
            }
        }
        ArrayList<Integer> list0 = new ArrayList<>();
        int index = (int) (Math.random() * diffNum);
        for (int i = 0; i < diffNum; i++) {
            list0.add(list.get(i));
            if (i != index) {
                list0.add(list.get(i));
                list0.add(list.get(i));
            }
        }

        Collections.shuffle(list0);
        Integer[] array = list0.toArray(new Integer[list0.size()]);

        for (int i = 0; i < array.length; i++) {
            //打印出構造的無序數組
            System.out.println("findSpecialNum--" + array[i]);
        }

        for (int i = 0; i < array.length; i++) {
            int count = 0;
            int x = array[i];
            for (int j = 0; j < array.length; j++) {
                if(array[j]==x){
                    count++;
                }

            }
            if(count >= 3){
                continue;
            }else{
                System.out.println("findSpecialNum--is=" + array[i]);
            }
        }


    }

上面構造出來的數組是隨機的，每次運行後結果不同，但均能計算出特殊數字。

12-15 18:46:25.231 15036-15036/? I/System.out: findSpecialNum--96
12-15 18:46:25.231 15036-15036/? I/System.out: findSpecialNum--78
12-15 18:46:25.231 15036-15036/? I/System.out: findSpecialNum--78
12-15 18:46:25.231 15036-15036/? I/System.out: findSpecialNum--96
12-15 18:46:25.231 15036-15036/? I/System.out: findSpecialNum--83
12-15 18:46:25.231 15036-15036/? I/System.out: findSpecialNum--29
12-15 18:46:25.231 15036-15036/? I/System.out: findSpecialNum--96
12-15 18:46:25.231 15036-15036/? I/System.out: findSpecialNum--83
12-15 18:46:25.231 15036-15036/? I/System.out: findSpecialNum--83
12-15 18:46:25.231 15036-15036/? I/System.out: findSpecialNum--78
12-15 18:46:25.231 15036-15036/? I/System.out: findSpecialNum--is=29