Submission #956232

#	Time	Username	Problem	Language	Result	Execution time	Memory
956232		Iwanttobreakfree	Election (BOI18_election)	C++17	100 / 100	484 ms	28136 KiB

election

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

const int max_n = 5e5+2;
struct Node{
    int l = 0, r = 0, sum = 0, sol = 0; 
};
Node t[4*max_n];
// a > 0, a tiene t[a] platos sin pagar
Node merge(Node a, Node b) {
    Node ans;
    ans.l = max(a.l, a.sum+b.l);
    ans.r = max(b.r, b.sum+a.r);
    ans.sum = a.sum+b.sum;
    ans.sol = max(a.l+b.r, max(a.sum+b.sol, a.sol+b.sum));
    return ans;
}

Node updateN(Node x, int p) {
    if (p > 0) x.l = x.r = x.sum = x.sol = x.sum+p;
    else x.sum += p;
    return x;
}

void update_p(int n, int l, int r, int p, int x) {
    if (l > p || r < p) return;
    if (l == r) {
        t[n] = updateN(t[n],x);
    }
    else {
        int mid = (r+l)/2;
        update_p(2*n, l, mid, p, x);
        update_p(2*n+1, mid+1, r, p, x);
        t[n] = merge(t[2*n], t[2*n+1]);
        //cout << l << ' ' << r << ' ' << t[n].valL << ' ' << t[n].valR << '\n';
    }
}

Node val(int n, int l, int r, int l2, int r2) {
    if (l > r2 || r < l2) return Node();
    if (l >= l2 && r <= r2) return t[n];
    int mid = (r+l)/2;
    Node L = val(2*n, l, mid, l2, r2);
    Node R = val(2*n+1, mid+1, r, l2, r2);
    return merge(L, R);
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    string s;
    cin >> n >> s;
    for (int i = 0; i < n; ++i) {
        if (s[i] == 'C') update_p(1, 0, max_n-1, i, -1);
        else update_p(1, 0, max_n-1, i, 1);
    }
    int q;
    cin >> q;
    while (q--) {
        int x, y;
        cin >> x >> y;
        --x;--y;
        Node ans = val(1, 0, max_n-1, x, y);
        //cout << ans.valL << ' ' << ans.valR << '\n';
        cout << ans.sol << '\n';
    }
}

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