题解 | #学英语#

#include <iostream>
#include <map>
#include <string>
#include <vector>

using namespace std;

void getResult(vector<string> &result, int &num);

int main() {
    long num;
    cin >> num;
    
    vector<string> result;
    
    int numMillion = num / 1000000;
    if (numMillion > 0) {
        getResult(result, numMillion);
        result.push_back("million");
    }
    
    int numThousand = num % 1000000 / 1000;
    if (numThousand > 0) {
        getResult(result, numThousand);
        result.push_back("thousand");
    }
    
    int numOne = num % 1000000 % 1000;
    if (numOne > 0) {
        getResult(result, numOne);
    }
    
    for (auto s : result) {
        cout << s << " ";
    }
    cout << endl;
    
    return 0;
}

void getResult(vector<string> &result, int &num) {
    map<int, string> u10 = {
        {1, "one"},
        {2, "two"},
        {3, "three"},
        {4, "four"},
        {5, "five"},
        {6, "six"},
        {7, "seven"},
        {8, "eight"},
        {9, "nine"}
    };
    map<int, string> u20 = {
        {10, "ten"},
        {11, "eleven"},
        {12, "twelve"},
        {13, "thirteen"},
        {14, "fourteen"},
        {15, "fifteen"},
        {16, "sixteen"},
        {17, "seventeen"},
        {18, "eighteen"},
        {19, "nineteen"}
    };
    map<int, string> u100 = {
        {2, "twenty"},
        {3, "thirty"},
        {4, "forty"},
        {5, "fifty"},
        {6, "sixty"},
        {7, "seventy"},
        {8, "eighty"},
        {9, "ninety"}
    };
    
    bool hundredSign = false;
    bool tenSign = false;
    if (num >= 100) {
        hundredSign = true;
        result.push_back(u10[num / 100]);
        result.push_back("hundred");
        num %= 100;
    }
    if (num >= 10) {
        tenSign = true;
        if (hundredSign) {
            result.push_back("and");
        }
        if (num <= 19) {
            result.push_back(u20[num]);
            num = 0;
        }
        else {
            result.push_back(u100[num / 10]);
            num %= 10;
        }
    }
    if (num > 0) {
        if (hundredSign && !tenSign) {
            result.push_back("and");
        }
        result.push_back(u10[num]);
    }
}