Codeforces Round #604 (Div. 2), problem: (A) Beautiful String

#include<bits/stdc++.h>
using namespace std;
#define sf scanf
#define pf printf
#define pb push_back
#define pob pop_back
#define all(a) a.begin(),a.end()
#define fio ios_base::sync_with_stdio(false); cin.tie(0);cout.tie(0);
#define i64 long long int
#define mem(x,y) memset(x,y,sizeof(x))
#define fill(arr,b) fill(arr, arr+sizeof(arr)/sizeof(arr[0]), b)
 
const double pi = acos(-1.0);
const int maxn = (i64)2e5+5;
 
int main(){
    //freopen("r","input.txt",stdin);
    int t;
    cin>>t;
    while(t--)
    {
 
        string s;
        int i;
        cin>>s;
        int sz = s.size();
        bool fg = true;
        if(sz == 1 && s[0] == '?')
        {
            cout<<"a"<<endl;
            continue;
 
        }
        for( i = 0 ; i<sz-1 ; i++)
        {
            if(s[i] == s[i+1] && s[i]!='?')
            {
                fg = false;
                break;
            }
            else if(s[i] == '?' && i == 0)
            {
                if(s[i+1] == 'a' || s[i+1] == '?') s[i] = 'b';
                else if(s[i+1] == 'b') s[i] = 'a';
                else if(s[i+1] == 'c') s[i] = 'b';
            }
            else if(s[i] == '?' && i != 0)
            {
                if((s[i-1] == 'a' && s[i+1] == 'b') || (s[i-1] == 'b' && s[i+1] == 'a')) s[i] = 'c';
                else if((s[i-1] == 'b' && s[i+1] == 'c') || (s[i-1] == 'c' && s[i+1] == 'b')) s[i] = 'a';
                else if((s[i-1] == 'a' && s[i+1] == 'c') || (s[i-1] == 'c' && s[i+1] == 'a')) s[i] = 'b';
                else if(s[i-1] == 'a' && s[i+1] == 'a') s[i] = 'b';
                else if(s[i-1] == 'b' && s[i+1] == 'b') s[i] = 'a';
                else if(s[i-1] == 'c' && s[i+1] == 'c') s[i] = 'a';
                else if(s[i-1] == 'a' && s[i+1] == '?') s[i] = 'b';
                else if(s[i-1] == 'b' && s[i+1] == '?') s[i] = 'c';
                else if (s[i-1] == 'c' && s[i+1] == '?') s[i] = 'a';
                else if(s[i-1] == 'a' && i == sz-1) s[i] = 'b';
                else if(s[i-1] == 'b' && i == sz-1) s[i] = 'c';
                else if (s[i-1] == 'c' && i==sz-1) s[i] = 'a';
            }
 
        }
        if(s[i-1] == 'a' && s[i] == '?') s[i] = 'b';
        else if(s[i-1] == 'b' && s[i] == '?') s[i] = 'c';
        else if (s[i-1] == 'c' && s[i] == '?') s[i] = 'a';
 
        if(fg)
        {
            for(i = 0 ; i<sz ; i++) cout<<s[i];
            cout<<endl;
        }
        else if(!fg) cout<<"-1"<<endl;
    }
return 0;
}