Submission #331760

#	Time	Username	Problem	Language	Result	Execution time	Memory
331760		smax	Election (BOI18_election)	C++17	100 / 100	564 ms	43416 KiB

election

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

#ifdef LOCAL
#define DEBUG(...) debug(#__VA_ARGS__, __VA_ARGS__);
#else
#define DEBUG(...) 6;
#endif

template<typename T, typename S> ostream& operator << (ostream &os, const pair<T, S> &p) {return os << "(" << p.first << ", " << p.second << ")";}
template<typename C, typename T = decay<decltype(*begin(declval<C>()))>, typename enable_if<!is_same<C, string>::value>::type* = nullptr>
ostream& operator << (ostream &os, const C &c) {bool f = true; os << "["; for (const auto &x : c) {if (!f) os << ", "; f = false; os << x;} return os << "]";}
template<typename T> void debug(string s, T x) {cerr << s << " = " << x << "\n";}
template<typename T, typename... Args> void debug(string s, T x, Args... args) {cerr << s.substr(0, s.find(',')) << " = " << x << " | "; debug(s.substr(s.find(',') + 2), args...);}

struct Node {
    int pref, suff, sum, ans;

    void leaf(char c) {
        pref = suff = ans = c == 'T';
        sum = c == 'T' ? 1 : -1;
    }

    void pull(Node &a, Node &b) {
        pref = max(a.pref, a.sum + b.pref);
        suff = max(b.suff, b.sum + a.suff);
        sum = a.sum + b.sum;
        ans = max({a.ans + b.sum, b.ans + a.sum, a.pref + b.suff});
    }
};

struct SegmentTree {
    int n;
    string s;
    vector<Node> st;

    SegmentTree(int _n) : n(_n), st(4*n) {
        build(1, 0, n-1);
    }

    SegmentTree(const string &_s) : n(_s.size()), s(_s), st(4*n) {
        build(1, 0, n-1);
    }

    void build(int p, int l, int r) {
        if (l == r) {
            st[p].leaf(s[l]);
            return;
        }

        int m = (l + r) / 2;
        build(2*p, l, m);
        build(2*p+1, m+1, r);
        st[p].pull(st[2*p], st[2*p+1]);
    }

    Node query(int p, int l, int r, int i, int j) {
        if (l == i && r == j)
            return st[p];

        int m = (l + r) / 2;
        if (j <= m)
            return query(2*p, l, m, i, j);
        else if (i > m)
            return query(2*p+1, m+1, r, i, j);
        Node ret, ls = query(2*p, l, m, i, m), rs = query(2*p+1, m+1, r, m+1, j);
        ret.pull(ls, rs);
        return ret;
    }

    int query(int i, int j) {
        return query(1, 0, n-1, i, j).ans;
    }
};

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int n, q;
    string s;
    cin >> n >> s >> q;
    SegmentTree st(s);
    for (int i=0; i<q; i++) {
        int l, r;
        cin >> l >> r;
        l--, r--;
        cout << st.query(l, r) << "\n";
    }

    return 0;
}

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