【解题报告】lintcode3统计数字

题意

解题

代码

class Solution {
    /*
     * param k : As description.
     * param n : As description.
     * return: An integer denote the count of digit k in 1..n
     */
     public int digitCounts(int k, int n) {
        // write your code here
        if (n == 0&&k == 0)
            return 1;
        if (n == 0&&k != 0)
            return 0;

        int dig = (int)(Math.log(n)/Math.log(10)) +1;
        int[] num = new int[dig];
        int count = 0,i = 0,digs = 1;
        while (i < n){
              num[0]++;
            i++;
              for (int j = 0;j < digs&&j < num.length;j++){
                    if (num[j] >= 10){
                        if (j < num.length - 1)
                        num[j+1] += num[j]/10;
                        num[j] %= 10;
                        if (j == (digs -1))
                        digs++;
                    }
                    if (num[j] == k)
                        count++;
            }
          
        }
            if (k == 0)
            count++;
    return count;
    }
};