算法

每日leetcode-273

将非负整数转换为其对应的英文表示。可以保证给定输入小于 231 - 1 。

示例 1:

输入: 123
输出: “One Hundred Twenty Three”
示例 2:

输入: 12345
输出: “Twelve Thousand Three Hundred Forty Five”
示例 3:

输入: 1234567
输出: “One Million Two Hundred Thirty Four Thousand Five Hundred Sixty Seven”
示例 4:

输入: 1234567891
输出: “One Billion Two Hundred Thirty Four Million Five Hundred Sixty Seven Thousand Eight Hundred Ninety One”

来源：力扣（LeetCode）
链接：https://leetcode-cn.com/problems/integer-to-english-words
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解

这个题很简单，直接按照三位分开之后分别转换就行，重点在于单词拼写

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class Solution {
public:
    string numberToWords(int num) {
        int splited[4] = { 0 };
        string numbers[] = {"", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"};
        string tensnumbers[] = {"", "", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"};
        string biggertennumbers[] = {"Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"};
        if (num == 0) {
            return "Zero";
        }
        for (int i = 0; i < 4; i++) {
            splited[i] = num % 1000;
            num = num / 1000;
        }
        string ans = "";
        for (int i = 3; i >= 0; i--) {
            int data = splited[i];
            if (data > 0) {
                if (data / 100) {
                    ans += numbers[data / 100] + " Hundred ";
                }
                data = data % 100;
                if (data > 0) {
                    if (data < 10) {
                        ans += numbers[data] + " ";
                    }
                    else if (data >= 20) {
                        ans += tensnumbers[data / 10] + " ";
                        data = data % 10;
                        if (data > 0) {
                            ans += numbers[data] + " ";
                        }
                    }
                    else {
                        ans += biggertennumbers[data - 10] + " ";
                    }
                }
                if (i == 3) {
                    ans += "Billion ";
                }
                else if (i == 2) {
                    ans += "Million ";
                }
                else if (i == 1) {
                    ans += "Thousand ";
                }
            }
        }
        return ans.substr(0, ans.size() - 1);
    }
};