class Solution {
public:
    vector<int> findNumsAppearOnce(vector<int>& nums) {
        int length = nums.size();
        vector<int> res;
        if(length<2) return res;

        // 对原始数组每个元素求异或
        int OR = 0;
        for(int i=0;i<length;i++){
            OR ^= nums[i];
        }

        unsigned int indexOf1 = findFirstBit1(OR);
        int num1=0,num2=0;
        for(int i=0;i<length;i++){
            if(isBit1(nums[i],indexOf1)){
                num1 ^= nums[i];
            }
            else{
                num2 ^= nums[i];
            }
        }
        res.push_back(num1);
        res.push_back(num2);
        return res;
    }
    int findFirstBit1(int num){
        unsigned int index = 0;
        while((num&1)==0 && (index<8*sizeof(unsigned int))){
            num = num>>1;
            index++;
        }
        return index;
    }
    bool isBit1(int num,int index){
        num = num>>index;
        return (num&1);
    }
};