[AtCoder] D - ABC Transform

D - ABC Transform

  • Time : O(q * log(min(t, k)))
  • Space : O(1)
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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")

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

#define MAX_N 1010101
#define INF 987654321
#define EPS 1e-9
#define ll long long
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vall3 vector<array<ll,3>>
#define all3 array<ll,3>
#define all5 array<ll,5>
#define vall5 vector<all5>
#define vll vector<ll>
#define vi vector<int>
#define vs vector<string>
#define usll unordered_set<ll>
#define uspll unordered_set<pll, PairHash>
#define umll unordered_map<ll,ll>
#define vvs vector<vs>
#define vvll vector<vll>
#define all(a) begin(a), end(a)
#define rall(a) rbegin(a), rend(a)

ll __gcd(ll x, ll y) { return !y ? x : __gcd(y, x % y); }

using namespace std;

char helper(char ch, ll n) {
return char('A' + (ch - 'A' + n) % 3);
}

char solve(string &s, ll t, ll k) {
if(t == 0) return s[k];
if(k == 0) return helper(s[0], t);
return helper(solve(s, t - 1, k / 2), (k & 1) + 1);
}

int main() {
ios_base::sync_with_stdio(0);
ios::sync_with_stdio(0);
cin.tie(0);
ll tc = 1;
//cin>>tc;
for (ll i = 1; i <= tc; i++) {
string s;
cin >> s;
ll q, t, k;
cin >> q;
for (ll j = 0; j < q; j++) {
cin >> t >> k;
cout << solve(s, t, k - 1) << endl;
}
}
return 0;
}
Author: Song Hayoung
Link: https://songhayoung.github.io/2022/06/20/PS/AtCoder/abc242-d/
Copyright Notice: All articles in this blog are licensed under CC BY-NC-SA 4.0 unless stating additionally.