LeetCode-504. Base 7 (Java)

Given an integer, return its base 7 string representation.

Example 1:

Input: 100Output: "202"

Example 2:

Input: -7Output: "-10"

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题意

10进制转7进制

思路

我第一思路就是辗转相除法

代码

public class Solution {    public String convertToBase7(int num) {        StringBuilder builder = new StringBuilder();if(num ==0) return 0+"";int absNum = Math.abs(num);        while(absNum !=0){             int result = absNum%7;             absNum = absNum/7;             builder.insert(0,result+"");                        }        if(num <0){             builder.insert(0,"-");        }        System.out.println("result : "+ builder.toString());        return builder.toString();    }}

其中builder.insert(0,result+"");  表示在字符串的第一位插入result。

还有一个更简单的方法：

    public static String convertToBase7(int num) {        return Integer.toString(num,7);    }