JZ31 整数中1出现的次数（从 1 到 n 整数中 1 出现的次数）

https://www.nowcoder.com/practice/bd7f978302044eee894445e244c7eee6

import java.lang.StringBuilder;

public class Solution {
    public int NumberOf1Between1AndN_Solution(int n) {
        StringBuilder temp = new StringBuilder();
        for (int i = 1; i <= n; i++) {
            temp.append(i);
        }
        
        char[] chs = temp.toString().toCharArray();
        int res = 0;
        for (int i = 0; i < chs.length; i++) {
            if (chs[i] == '1') {
                res++;
            }
        }
        
        return res;
    }
}