can anyone pls explain me why this code is not working for ques B. Decode String

while testing with the all 9 test cases(which is given in ques) this test case 5 11111 is giving me wrong ans while testing it separately it is giving the right ans

#include<bits/stdc++.h> using namespace std; typedef long long li; int main(){ ** li t;** ** cin>>t;** ** string ans="abcdefghijklmnopqrstuvwxyz";** ** while(t--){** ** li n;** ** cin>>n;** ** string s;** ** cin>>s;** ** string res="";** ****
** for(li i=0;i<s.length();i++){** ** if( s[i+2]=='0' && s[i+3]!='0' && i<n){** ** res+=ans[(s[i]-'0')*10+(s[i+1]-'0'-1)];** ** i+=2;** ** }else{** ** res+=ans[s[i]-'0'-1];** ** }** ** }** ** cout<<res<<endl;** ** }** ** return 0;** } **** ****