https://leetcode.cn/problems/minimize-xor/

二进制下的贪心。（用bitset更方便)

class Solution {
public:
    int minimizeXor(int num1, int num2) {
        bitset<32> b1(num1), b2(num2), b3;
        int cnt_2 = b2.count();
        for(int i = 31; i >= 0 && cnt_2 > 0; i--){
            if(b1[i] == 1){
                b3[i] = 1;
                cnt_2--;  
            }
        }
        for(int i = 0; i < 32 && cnt_2 > 0; i++){
            if(b3[i] == 0){
                b3[i] = 1;
                cnt_2--; 
            }
        }
        return int(b3.to_ulong());
        
    }
};