poj 2033 Alphacode

#include <iostream>using namespace std;const int MAXN = 50000;int main(){      __int64 dp[MAXN];      char s[MAXN];      while(scanf("%s", s + 1) != EOF) {int len = strlen(s + 1);if(len == 1 && s[1] == '0') break;dp[0] = dp[1] = 1;for(int i = 2; i <= len; i++) {     if(s[i] != '0') {dp[i] = dp[i - 1];int num = (s[i - 1] - '0') * 10 + (s[i] - '0');if(num >= 11 && num <= 26) dp[i] += dp[i - 2];     }else{if(s[i - 1] == '0') dp[i] == dp[i - 1];else if(s[i - 1] == '1' || s[i - 1] == '2') dp[i] = dp[i - 2];     }}printf("%I64dn", dp[len]);      }      return(0);}