[AtCoder] D - Coloring Dominoes

D - Coloring Dominoes

  • Time : O(n)
  • Space : O(n)
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#include <bits/stdc++.h>

#pragma optimization_level 3
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("Ofast")//Comment optimisations for interactive problems (use endl)
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")

using namespace std;

struct PairHash {inline std::size_t operator()(const std::pair<int, int> &v) const { return v.first * 31 + v.second; }};

// speed
#define Code ios_base::sync_with_stdio(false);
#define By ios::sync_with_stdio(0);
#define Sumfi cout.tie(NULL);

// alias
using ll = long long;
using ld = long double;
using ull = unsigned long long;

// constants
const ld PI = 3.14159265358979323846; /* pi */
const ll INF = 1e18;
const ld EPS = 1e-9;
const ll MAX_N = 202020;
const ll mod = 1e9 + 7;

// typedef
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;
typedef array<ll,3> all3;
typedef array<ll,5> all5;
typedef vector<all3> vall3;
typedef vector<all5> vall5;
typedef vector<ld> vld;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<int> vi;
typedef pair<string, string> pss;
typedef vector<pss> vpss;
typedef vector<string> vs;
typedef vector<vs> vvs;
typedef unordered_set<ll> usll;
typedef unordered_set<pll, PairHash> uspll;
typedef unordered_map<ll, ll> umll;
typedef unordered_map<pll, ll, PairHash> umpll;

// macros
#define rep(i,m,n) for(ll i=m;i<n;i++)
#define rrep(i,m,n) for(ll i=n;i>=m;i--)
#define all(a) begin(a), end(a)
#define rall(a) rbegin(a), rend(a)
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
#define ASCEND(a) iota(all(a),0)
#define sz(x) ll((x).size())
#define pyes cout<<"YES\n";
#define pno cout<<"NO\n";
#define pneg1 cout<<"-1\n";
#define CASE(x) cout<<"Case #"<<x<<": ";

// utility functions
template <typename T>
void print(T &&t) { cout << t << "\n"; }
template<typename T>
void printv(vector<T>v){ll n=v.size();rep(i,0,n)cout<<v[i]<<" ";cout<<"\n";}
void fileIO() {freopen("input.txt","r",stdin); freopen("output.txt","w",stdout);}
//void readf() {freopen("", "rt", stdin);}


ll __gcd(ll x, ll y) { return !y ? x : __gcd(y, x % y); }
ll __lcm(ll x, ll y) { return x * y / __gcd(x,y); }
ll modpow(ll n, ll x, ll MOD = mod) { if(!x) return 1; ll res = modpow(n,x>>1,MOD); res = (res * res) % MOD; if(x&1) res = (res * n) % MOD; return res; }

ll dp[55][1<<3][1<<3];

ll helper(vs& A, ll p, ll mask1, ll mask2) {
if(p == sz(A[0])) return 1;
if(dp[p][mask1][mask2] != -1) return dp[p][mask1][mask2];
ll& res = dp[p][mask1][mask2] = 0;

if(A[0][p] == A[1][p]) {
rep(i,0,3) {
if(mask1 & (1<<i)) continue;
if(mask2 & (1<<i)) continue;
res = (res + helper(A,p + 1, 1<<i, 1<<i)) % mod;
}
} else {
rep(i,0,3) {
rep(j,0,3) {
if(i == j) continue;
if(mask1 & (1<<i)) continue;
if(mask2 & (1<<j)) continue;
res = (res + helper(A,p + 2, 1<<i, 1<<j)) % mod;
}
}
}
return res;
}

ll solve(vs& A) {
MINUS(dp);
return helper(A,0,0,0);
}

int main() {
Code By Sumfi

cout.precision(12);

ll tc = 1;
//cin>>tc;
rep(i,1,tc+1) {
ll n;
cin>>n;
vs A(2);
cin>>A[0]>>A[1];
print(solve(A));
}

return 0;
}
Author: Song Hayoung
Link: https://songhayoung.github.io/2022/08/14/PS/AtCoder/arc081-b/
Copyright Notice: All articles in this blog are licensed under CC BY-NC-SA 4.0 unless stating additionally.