[Codeforces] VK Cup 2012 Qualification Round 2 C. String Manipulation 1.0

VK Cup 2012 Qualification Round 2 C. String Manipulation 1.0

  • Time : O(qnlogn)
  • Space : O(nk)
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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 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 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 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 fenwick[26][MAX_N];
void update(ll k, ll n, ll v) {
while(n < MAX_N) {
fenwick[k][n] += v;
n += n & -n;
}
}

ll query(ll k, ll n) {
ll res = 0;
while(n) {
res += fenwick[k][n];
n -= n & - n;
}
return res;
}

string solve(string& s, ll k, vector<pair<ll, char>>& Q) {
auto idxOf = [](char ch) { return ch - 'a';};
ll real = 0;
unordered_map<ll, vll> mp;
rep(i,0,k) {
rep(j,0,sz(s)) {
mp[idxOf(s[j])].push_back(real++);
}
}
rep(i,0,sz(Q)) {
auto [pos, ch] = Q[i];
auto& vec = mp[idxOf(ch)];
ll last = 0, qry = -1;
ll real = pos;
while((qry = query(idxOf(ch), real)) != last) {
real += qry - last;
last = qry;
}

vec[real - 1] = -1;

update(idxOf(ch), real, 1);
}
vector<pair<ll,char>> A;
rep(i,0,26) {
rep(j,0,sz(mp[i])) {
if(mp[i][j] == -1) continue;
A.push_back({mp[i][j], i + 'a'});
}
}
sort(all(A));
string res = "";
rep(i,0,sz(A)) {
auto [_, ch] = A[i];
res.push_back(ch);
}
return res;
}

int main() {
Code By Sumfi

cout.precision(12);

ll tc = 1;
//cin>>tc;
rep(i,1,tc+1) {
ll k, n;
string s;
cin>>k>>s>>n;
vector<pair<ll, char>> A(n);
rep(i,0,n) cin>>A[i].first>>A[i].second;
print(solve(s,k,A));
}
return 0;
}
Author: Song Hayoung
Link: https://songhayoung.github.io/2022/08/05/PS/Codeforces/vk-cup-2012-quali-2-c/
Copyright Notice: All articles in this blog are licensed under CC BY-NC-SA 4.0 unless stating additionally.