【简单】Lintcode 1385:Lucky Number Eight

8 is the lucky number of Xiaojiu. Xiaojiu wants to know how many numbers in the numbers 1~n contain 8.

 Notice

• 1 <= n <= 1000000

Example

Given n = 20, return 2.

Explanation:
Only 8,18 contains 8.

Given n = 100, return 19.

Explanation:
8,18,28,38,48,58,68,78,80,81,82,83,84,85,86,87,88,89,98 contains 8.

解题思路：

    从1到n遍历，把其中每一个数拆分数字，一旦发现有8存在即count++，跳出，继续下一个数字的考察。

    注意在遍历里面不能直接用i来拆分，这样会引起遍历始终从零开始，所以需要复制出来操作，i仅用作次数循环。

class Solution {
public:
    /**
     * @param n: count lucky numbers from 1 ~ n
     * @return: the numbers of lucky number
     */
    int luckyNumber(int n) 
    {
        // Write your code here
        int count = 0;

        for(int i=1;i<=n;i++)
        {
            int t=i;
            while(t)
            {
                if(t%10 == 8)
                {
                    count++;
                    break;
                }
                t = t/10;
            }
        }
    
        return count;

    }
};