题解 | 数字序列中某一位的数字

难不是很难，就是很容易错，一定要多做调试！

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param n int整型
     * @return int整型
     */
    public int findNthDigit (int n) {
        // write code here
        int nc = n;
        int k = 1;
        int bit = 0;
        int ibit = 1;
        if (nc < 10) {
            return n;
        }
        nc = nc - 9;
        bit = 9;
        while (nc > 0) {
            ibit = ibit * 10;
            k = k + 1;
            bit = k * ibit * 9;
            nc = nc - bit;
        }
        nc = nc + bit-1;
        int a = nc % k;
        int b = nc / k;
        int r = 0;
        r =  ibit + b;
        
        // 将数字转换为字符串
        String numberStr = Integer.toString(r);
        char digitChar = numberStr.charAt(a);
        return Character.getNumericValue(digitChar);
    }
}