leetcode

0 class Solution {

1 public:

2 string decodeAtIndex(const string &s, int k) {

3 long n = 0, idx;

4

5 for (idx = 0; n < k; idx++) {

6 n = isdigit(s[idx]) ? n * (s[idx] & 0x0F) : n + 1;

7 }

8

9 while (idx--) {

10 if (isdigit(s[idx]))

11 n /= s[idx] & 0x0F, k %= n;

12 else if (k % n == 0)

13 return string(1, s[idx]);

14 else

15 n--;

16 }

17 return "";

18 }

19 };