Submission #1529270

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Source Code Expand

#include <bits/stdc++.h>
#define debug(x) //cout << #x << " = " << x << endl;
#define rep(i, a, b) for(int i=a; i<b; i++)

using namespace std;

typedef long long ll;

ll start(const string a, const string b){
  if( a[0] == b[0] )
    return 3LL;
  else
    return 6LL;
}

ll transition(const string a, const string b, int i){
  if( a[i] == b[i] ){
    if( a[i+1] == b[i+1] ) return 2LL;
    else return 2LL;    
  }else{
    if( a[i+1] == b[i+1] ) return 1LL;
    else return 3LL;
  }
}

int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(0); cout.tie(0);
  
  //const ll mod = 1000000007;
  const ll mod = 1e9+7;

  int n;
  cin >> n;
  string s1, s2;
  cin >> s1 >> s2;

  ll ans = start(s1, s2);
  debug(ans);

  int i = 0;
  if( ans == 6 )
    i++;

  while( i < s1.size()-1 ){
    ll tr = transition(s1, s2, i);
    ans = (ans*tr)%mod;
    debug(ans);
    if( s1[i+1] == s2[i+1] )
      i++;
    else
      i += 2;
    if( i == s1.size()-1) break;
  }

  cout << ans << endl;

  return 0;
}

Submission Info

Judge Result