Submission #1209107

#	Time	Username	Problem	Language	Result	Execution time	Memory
1209107		vanea	Election (BOI18_election)	C++20	100 / 100	592 ms	20380 KiB

election

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

string s;
const int mxN = 2e6+10;
array<int, 4> st[mxN];

array<int, 4> comb(array<int, 4> a, array<int, 4> b) {
    array<int, 4> ans;
    ans[0] = a[0] + b[0];
    ans[1] = max(a[1], a[0] + b[1]);
    ans[2] = max(b[2], b[0] + a[2]);
    ans[3] = max({a[0]+b[3], a[3]+b[0], a[1]+b[2]});
    return ans;
}

void build(int node, int l, int r) {
    if(l == r) {
        if(s[l] == 'T') st[node] = {1, 1, 1, 1};
        else st[node] = {-1, 0, 0, 0};
        return ;
    }
    int mid = (l+r)/2;
    build(node*2, l, mid);
    build(node*2+1, mid+1, r);
    st[node] = comb(st[node*2], st[node*2+1]);
}

array<int, 4> qry(int node, int l, int r, int l1, int r1) {
    if(l1 <= l && r <= r1) return st[node];
    if(l > r1 || l1 > r) return {0, 0, 0, 0};
    int mid = (l+r)/2;
    return comb(qry(node*2, l, mid, l1, r1),
                qry(node*2+1, mid+1, r, l1, r1));
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n;
    cin >> n;
    cin >> s;
    int q;
    cin >> q;
    build(1, 0, n-1);
    while(q--) {
        int l, r;
        cin >> l >> r; --l; --r;
        array<int, 4> now = qry(1, 0, n-1, l, r);
        cout << now[3] << '\n';
    }
    return 0;
}

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