Leetcode. Decode Ways

A message containing letters from was A-Z being encoded to numbers using the following mapping:

' A '-1 ' B '-2 ... ' Z '-26

Given an encoded message containing digits, determine the total number of ways to decode it.

For example,
Given encoded message "12" , it could be decoded as "AB" (1 2) or "L" (12).

The number of ways decoding is "12" 2.

1     intNumdecodings (strings)2     {3         intn =s.size (), ret;4         if(N <1|| s[0] =='0')5             return 0;6             7         int*ways =New int[n +1], I;8ways[0] =1;9ways[1] =1;Ten          for(i =1; I < n; i++) One         { A             if(S[i] = ='0') -             { -                 if(S[i-1] =='0'|| S[i-1] >'2') the                     return 0; -                 Else -Ways[i +1] = ways[i-1]; -             } +             Else if(S[i] <='6') -             { +                 if(S[i-1] =='0'|| S[i-1] >'2') AWays[i +1] =Ways[i]; at                 Else -Ways[i +1] = Ways[i] + ways[i-1]; -             } -             Else -             { -                 if(S[i-1] =='1') inWays[i +1] = Ways[i] + ways[i-1]; -                 Else toWays[i +1] =Ways[i]; +             } -         } the          *RET =Ways[n]; $ delete[] ways;Panax Notoginseng         returnret; -}

Leetcode. Decode Ways