273. 整数转换英文表示

没啥看的必要。。
可读性差（变量名瞎取）
就比较烦的模拟

class Solution {
public:
    vector<string> ge={"","One","Two","Three","Four","Five","Six","Seven","Eight","Nine"};
    vector<string> ershi={"Ten","Eleven","Twelve","Thirteen","Fourteen","Fifteen","Sixteen","Seventeen","Eighteen","Nineteen",};
    vector<string> shi={"0","1","Twenty","Thirty","Forty","Fifty","Sixty","Seventy","Eighty","Ninety"};
    vector<string> wei={"","","Thousand","Million","Billion"};
    
    vector<int>getnum(int num){
        vector<int>res;
        string sn=to_string(num);
        
        int t=(3-sn.size()%3)%3;
        sn=string(t,'0')+sn;

        for(int i=0;i<sn.size();i+=3){
            string tmp=sn.substr(i,3);
            res.push_back(atoi(tmp.c_str()));
        }
        return res;
    }
    
    string get3(int n){
        string res;
        int n1=n/100,n3=n%10,n2=n/10%10;
        if(n1)res+=ge[n1]+" Hundred ";
        if(n2){
            if(n2==1 && n3==0)res +="Ten ";
            if(n2==1 && n3!=0)res+=ershi[n3]+" ";
            if(n2>1)res+=shi[n2]+" ";
        }
        if(n3){
            if(n2!=1)res +=ge[n3]+" ";
        }
        return res;
    }
    
    string numberToWords(int num) {
        if(!num)return "Zero";
        vector<int>vec=getnum(num);
        int n=vec.size();
        string res;
        for(int i=0;i<n;i++){
            res+=get3(vec[i]);
            if(vec[i])res +=wei[n-i]+" ";
        }
        while(res.back()==' ')res.pop_back();
        
        return res;
    }
};