package leetcode;

public class Q137_SingleNumberII {

public static int singleNumber(int[] nums) { //自己模拟三进制运算

int[] w = new int[Integer.SIZE];

for(int i=0; i<nums.length; i++){

for(int j = 0; j < Integer.SIZE; j++){

w[j] = (w[j] + ((nums[i] >> j) & 1)) % 3;

}

}

int ans = 0;

for(int i=0; i<Integer.SIZE; i++)

ans += w[i] << i;

return ans;

}

public static int singleNumber2(int[] nums){

int one = 0, two = 0, three = 0;

for(int i=0; i<nums.length; i++){

two |= (one & nums[i]);//two位：11才进位1

one ^= nums[i]; //one位：第一层异或

three = ~(one & two); //three 看不懂

one &= three;

two &= three;

}

return one;

}

public static void main(String[] args) {

System.out.println(singleNumber(new int[]{2,2,2,3}));

}

}