Submission #1266936

#	Time	Username	Problem	Language	Result	Execution time	Memory
1266936		glupan	Election (BOI18_election)	C++20	0 / 100	3 ms	320 KiB

election

#include <bits/stdc++.h>

#define ll long long

using namespace std;

const int MAX_N = 200005;

vector<pair<ll,ll>> treePref, treeSuf;

pair<ll,ll> query(int x, int lx, int rx, int l, int r) {
    if(lx > r or rx < l) return {0, 0};
    if(lx >= l and rx <= r) return treePref[x];
    int mid = (lx+rx)/2;
    pair<ll,ll> left = query(2*x, lx, mid, l, r);
    pair<ll,ll> right = query(2*x+1, mid+1, rx, l, r);
    return {left.first+right.first, max(left.second, left.first+right.second)};
}

pair<ll,ll> Query(int x, int lx, int rx, int l, int r) {
    if(lx > r or rx < l) return {0, 0};
    if(lx >= l and rx <= r) return treeSuf[x];
    int mid = (lx+rx)/2;
    pair<ll,ll> left = Query(2*x, lx, mid, l, r);
    pair<ll,ll> right = Query(2*x+1, mid+1, rx, l, r);
    return {left.first+right.first, max(right.second, right.first+left.second)};
}

void solve() {
    int n; cin >> n;
    string s; cin >> s;
    vector<int>a;
    for(int i=0; i<n; i++) {
        if(s[i] == 'C') a.push_back(-1);
        else a.push_back(1);
    }
    while(__builtin_popcount(n) != 1) {
        a.push_back(0);
        n++;
    }
    treePref.resize(2*n);
    treeSuf.resize(2*n);
    for(int i=0; i<n; i++) {
        treePref[n+i] = {a[i], a[i]};
        treeSuf[n+i] = {a[i], a[i]};
    }
    for(int i=n-1; i>0; i--) {
        treePref[i].first = treePref[2*i].first + treePref[2*i+1].first;
        treePref[i].second = max(treePref[2*i].second, treePref[2*i].first+treePref[2*i+1].second);
        treeSuf[i].first = treeSuf[2*i].first + treeSuf[2*i+1].first;
        treeSuf[i].second = max(treeSuf[2*i+1].second, treeSuf[2*i+1].first + treeSuf[2*i].second);
    }
    int q; cin >> q;
    while(q--) {
        int l,r;
        cin >> l >> r;
        l--; r--;
        cout << max(query(1,0,n-1,l,r).second,Query(1,0,n-1,l,r).second) << endl;
    }
}

int main() {
    int t=1;
    while(t--)
        solve();
}

• Subtask 1: 0 / 28
• Subtask 2: 0 / 54
• Subtask 3: 0 / 18