class Solution {
public:
    int rangeBitwiseAnd(int left, int right) {
        if(right-left<=1)
        {
            return right&left;
        }
        vector<int> a,b;
        while(left>0)
        {
            a.push_back(left%2);
            left/=2;
        }
        while(right>0)
        {
            b.push_back(right%2);
            right/=2;
        }
        if(a.size()!=b.size())
            return 0;
        int ans=0;
        for(int i=a.size()-1;i>=0;i--)
        {
            if(a[i]==b[i]&&a[i]==1)
            {
                ans+=pow(2,i);
            }
            else if(a[i]!=b[i])
                break;
        }
        return ans;
    }
};