今天和大家聊的问题叫做 整数转换英文表示，我们先来看题面：https://leetcode-cn.com/problems/integer-to-english-words/
Convert a non-negative integer num to its English words representation.
将非负整数 num 转换为其对应的英文表示。
示例
示例 1： 输入：num = 123 输出："One Hundred Twenty Three" 示例 2： 输入：num = 12345 输出："Twelve Thousand Three Hundred Forty Five" 示例 3： 输入：num = 1234567 输出："One Million Two Hundred Thirty Four Thousand Five Hundred Sixty Seven" 示例 4： 输入：num = 1234567891 输出："One Billion Two Hundred Thirty Four Million Five Hundred Sixty Seven Thousand Eight Hundred Ninety One"
解题
这个是网上比较好理解的了 。
class Solution { private final String[] THOUSAND = {"", "Thousand", "Million", "Billion"}; private final String[] LESS_THAN_TWENTY = {"", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"}; private final String[] HUNDRED = {"", "", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"}; public String numberToWords(int num) { if(num == 0) return "Zero"; StringBuilder sb = new StringBuilder(); int index = 0; while(num > 0) { if(num % 1000 != 0) { StringBuilder tmp = new StringBuilder(); helper(num % 1000, tmp); sb.insert(0, tmp.append(THOUSAND[index]).append(" ")); } index++; num /= 1000; } return sb.toString().trim(); } private void helper(int num, StringBuilder tmp) { if(num == 0) return; if(num < 20) { tmp.append(LESS_THAN_TWENTY[num]).append(" "); }else if(num < 100) { tmp.append(HUNDRED[num / 10]).append(" "); helper(num % 10, tmp); }else { tmp.append(LESS_THAN_TWENTY[num / 100]).append(" Hundred").append(" "); helper(num % 100, tmp); } } }
好了，今天的文章就到这里，如果觉得有所收获，请顺手点个在看或者转发吧，你们的支持是我最大的动力 。
