leetcode每日一题系列-整数转换英文表示-「英文水平」
leetcode-273-整数转换英文表示
[博客链接]
菜????的学习之路
掘金首页
[题目链接]
题目链接
[github地址]
github地址
[题目描述]
将非负整数 num 转换为其对应的英文表示。
示例 1：
输入：num = 123 输出："One Hundred Twenty Three" 复制代码
示例 2：
输入：num = 12345 输出："Twelve Thousand Three Hundred Forty Five" 复制代码
示例 3：
输入：num = 1234567 输出："One Million Two Hundred Thirty Four Thousand Five Hundred Sixty Seven" 复制代码
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" 复制代码
提示：
0 <= num <= 2312^{31}231 - 1
思路一：英文水平
大家就当来复习英文水平就好了
因为这道题感觉真的没啥考察价值虽然是道hard
但是英文不行哪怕他是easy也做不出来
999为一组，然后注意特殊的证书1-20 其余的就没啥了
枚举拼接即可
class Solution { static String[] num2str_small = { "Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen" }; static String[] num2str_medium = { "", "", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety" }; static String[] num2str_large = { "Billion", "Million", "Thousand", "", }; String num2Str(int x) { String ans = ""; if (x >= 100) { ans += num2str_small[x / 100] + " Hundred "; x %= 100; } if (x >= 20) { ans += num2str_medium[x / 10] + " "; x %= 10; } if (x != 0) ans += num2str_small[x] + " "; return ans; } public String numberToWords(int num) { if (num == 0) return num2str_small[0]; StringBuilder sb = new StringBuilder(); for (int i = (int)1e9, j = 0; i >= 1; i /= 1000, j++) { if (num < i) continue; sb.append(num2Str(num / i) + num2str_large[j] + " "); num %= i; } while (sb.charAt(sb.length() - 1) == ' ') sb.deleteCharAt(sb.length() - 1); return sb.toString(); } } 复制代码ps:这里用的三叶大佬的代码，我写这种代码丑陋的过分，还是用三叶的看着舒服
时间复杂度O(n)
作者：saberlgy
链接：https://juejin.cn/post/7017678426177798152