整数转换英文表示Java
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# 题目
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"
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"
提示：
0 <= num <= 2<sup>31</sup> - 1
# 思路
先初始化英文数组，然后对给定数字取模、除以等去解析，注意从哪个数组取
# 解法
class Solution {
String[] low = {"","One","Two","Three","Four","Five","Six","Seven","Eight","Nine"};
String[] mid = {"Ten","Eleven","Twelve","Thirteen","Fourteen","Fifteen","Sixteen","Seventeen","Eighteen","Nineteen"};
String[] high = {"","","Twenty","Thirty","Forty","Fifty","Sixty","Seventy","Eighty","Ninety"};
public String numberToWords(int num) {
if(num==0){
return "Zero";
}
int part1 = num%1000;
num = num/1000;
int part2 = num%1000;
num = num/1000;
int part3 = num%1000;
num = num/1000;
int part4 = num;
String ans = "";
if(part4!=0){
ans = buildNumber(part4) + "Billion ";
}
if(part3!=0){
ans = ans + buildNumber(part3) + "Million ";
}
if(part2!=0){
ans = ans + buildNumber(part2) + "Thousand ";
}
if(part1!=0){
ans = ans + buildNumber(part1);
}
return ans.trim();
}
public String buildNumber(int num){
int a = num%10;
num = num/10;
int b = num%10;
num = num/10;
int c = num;
String ans = "";
if(c!=0){
ans = low[c] + " " + "Hundred ";
}
if(b==1){
ans = ans + mid[a];
}else if(b==0){
ans = ans + low[a];
}else {
ans = ans + high[b] + " " + low[a];
}
return ans.trim() + " ";
}
}
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# 总结
- 分析出几种情况，然后分别对各个情况实现
