Submission #877129

#	Time	Username	Problem	Language	Result	Execution time	Memory
877129		amin_2008	Election (BOI18_election)	C++17	100 / 100	1273 ms	89912 KiB

election

#pragma GCC optimize ("O3")
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>

// author: amin_2008

#define ios          ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define ll           long long
#define vi           vector<int>
#define vs           vector<string>
#define vc           vector<char>
#define vl           vector<ll>
#define all(v)       v.begin(), v.end()
#define rall(v)      v.rbegin(), v.rend()
#define pb           push_back
#define bpc          __builtin_popcount
#define pii          pair<int, int>
#define pll          pair<ll, ll>
#define piii         pair<pii, int>
#define vpii         vector<pii>
#define vpll         vector<pll>
#define vvpii        vector<vpii>
#define vvi          vector<vector<int>>
#define vvl          vector<vector<ll>>
#define ins          insert
#define ts           to_string
#define F            first
#define S            second
#define lb           lower_bound
#define ub           upper_bound
#define ld           long double
#define ull          unsigned long long
#define endl         '\n'
//#define int          ll

using namespace std;
using namespace __gnu_pbds;
using namespace __cxx11;
template<class T> using ordered_set = tree<T, null_type,less<T>, rb_tree_tag,tree_order_statistics_node_update>;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const ll inf = 2e5 * 1e9;
const int mod = 1e9+7;
const int sz = 5e5+5;
const int N = 500001;
const int logg = 18;
const int P = 40000005;
const ll M = 8e5+5;

//int a[sz];
vi st[sz << 2]{vi(4)};

vi merge(vi a, vi b)
{
    vi res(4);
    res.front() = a.front() + b.front();
    res[1] = max(a[1], b[1] + a.front());
    res[2] = max(b[2], a[2] + b.front());
    res[3] = max(max(max(a[3] + b.front(), b[3] + a.front()), 0), a[1] + b[2]);
    return res;
}

string s;

void build(int l, int r, int in)
{
    if ( l == r )
    {
        int a = ( s[l] == 'T' ), b = a;
        if ( !b ) b--;
        st[in] = {b, a, a, a};
        return;
    }
    int mid = ( l + r ) >> 1;
    build(l, mid, in << 1);
    build(mid+1, r, in << 1 | 1);
    st[in] = merge(st[in << 1], st[in << 1 | 1]);
}

vi get(int a, int b, int l, int r, int in)
{
    if ( a > r or b < l )       return {0, 0, 0, 0};
    if ( a <= l and r <= b )    return st[in];
    int mid = ( l + r ) >> 1;
    return merge(get(a, b, l, mid, in << 1), get(a, b, mid+1, r, in << 1 | 1));
}

void solve()
{
    int n;
    cin >> n >> s;
    build(0, n - 1, 1);
    int q;
    cin >> q;
    while ( q-- )
    {
        int l, r;
        cin >> l >> r;
        l--, r--;
        cout << get(l, r, 0, n - 1, 1)[3] << endl;
    }
}

signed main()
{
    ios;
    //precompute();
    int t = 1;
    //cin >> t;
    while(t--){
        solve();
    }
}

• Subtask 1: 28 / 28
• Subtask 2: 54 / 54
• Subtask 3: 18 / 18