题解 | #阿拉伯数字转中文#

class Solution {
  public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param n int整型
     * @return string字符串
     */
    string A[10] = {"零", "一", "二", "三", "四", "五", "六", "七", "八", "九"};
    string B[4] = {"", "十", "百", "千"};
    string C[4] = {"", "万", "亿", "万亿"};
    vector<string> tmp;
    string ans = "";

    void fun2(int part, string ans) {
        bool lastZero = true;
        int pos = 0;
        while (part > 0) {
            int now = part % 10;
            part /= 10;
            if (now == 0) {
                if (!lastZero) {
                    tmp.push_back(A[0]);
                    lastZero = true;
                }
            } else {
                lastZero = false;
                tmp.push_back(B[pos]);
                tmp.push_back(A[now]);
            }
            pos++;
        }
    }

    string fun(int num) {
        if(num == 0)
            return A[0];
        int pos = 0;
        string ans = "";
        bool last = false;
        while (num > 0) {
            int part = num % 10000;
            num /= 10000;
            if (last) {
                tmp.push_back(A[0]);
                last = false;
            }
            if (part > 0 && part < 1000)
                last = true;
            if(part > 0)
                tmp.push_back(C[pos]);
            fun2(part, ans);
            pos++;
        }
        int n = tmp.size() - 1;
        if(n - 1 >= 0 && tmp[n - 1] == "十" && tmp[n] == "一")
            n--;
        for(int i = n; i >= 0; i--)
            ans += tmp[i];
        return ans;
    }

    string num2cn(int n) {
        // write code here
        if(n < 0) {
            ans = "负";
            n = -n;
        }
        ans += fun(n);
        return ans;
        
    }
};