Submission #572233

#	Time	Username	Problem	Language	Result	Execution time	Memory
572233		hoanghq2004	Election (BOI18_election)	C++14	100 / 100	1103 ms	48172 KiB

election

#include <bits/stdc++.h>
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace std;

template <typename T>
using ordered_set = tree <T, null_type, less <T>, rb_tree_tag, tree_order_statistics_node_update>;

const int N = 5e5 + 10;

int n, q;
int p[N], s[N], L[N], R[N];
char c[N];
int flag[N];

struct SegmentTree {
    int st[N * 4];
    int lazy[N * 4];
    void push(int id, int delta) {
        st[id] += delta;
        lazy[id] += delta;
    }
    void add(int id, int L, int R, int u, int v, int delta) {
        if (u > R || L > v) return;
        if (u <= L && R <= v) {
            push(id, delta);
            return;
        }
        push(id * 2, lazy[id]);
        push(id * 2 + 1, lazy[id]);
        lazy[id] = 0;
        int mid = L + R >> 1;
        add(id * 2, L, mid, u, v, delta);
        add(id * 2 + 1, mid + 1, R, u, v, delta);
        st[id] = min(st[id * 2], st[id * 2 + 1]);
    }
    int get(int id, int L, int R, int u, int v) {
        if (u > R || L > v) return 1e9;
        if (u <= L && R <= v) return st[id];
        push(id * 2, lazy[id]);
        push(id * 2 + 1, lazy[id]);
        lazy[id] = 0;
        int mid = L + R >> 1;
        return min(get(id * 2, L, mid, u, v), get(id * 2 + 1, mid + 1, R, u, v));
    }
} F, B;

int ans[N];

int main() {
    ios :: sync_with_stdio(0); cin.tie(0);
    cin >> n;
    for (int i = 1; i <= n; ++i) cin >> c[i];
    for (int i = 1; i <= n; ++i) p[i] = p[i - 1] + (c[i] == 'C' ? 1 : -1);
    vector <int> stk;
    for (int i = n; i >= 0; --i) {
        while (stk.size() && p[i] <= p[stk.back()]) {
            L[stk.back()] = i;
            stk.pop_back();
        }
        stk.push_back(i);
    }
    while (stk.size()) {
        L[stk.back()] = -1;
        stk.pop_back();
    }
    for (int i = 1; i <= n; ++i) F.add(1, 1, n, i, n, (c[i] == 'C' ? 1 : -1));
    for (int i = 1; i <= n; ++i) B.add(1, 1, n, 1, i, (c[i] == 'C' ? 1 : -1));
    cin >> q;
    vector <tuple <int, int, int>> work;
    for (int i = 0; i < q; ++i) {
        int u, v;
        cin >> u >> v;
        ans[i] = - min(0, F.get(1, 1, n, u, v) - p[u - 1]);
        work.push_back({u, v, i});
    }
    sort(work.begin(), work.end());
    vector <pair <int, int>> s;
    for (int i = 1; i <= n; ++i) s.push_back({L[i] + 1, i});
    sort(s.begin(), s.end());
    int j = 0;
    for (auto [u, v, i]: work) {
        while (j < s.size() && s[j].first < u) {
            B.add(1, 1, n, 1, s[j].second, 1);
            ++j;
        }
        int b = (v == n ? 0 : B.get(1, 1, n, v + 1, v + 1));
        ans[i] -= min(0, B.get(1, 1, n, u, v) - b);
    }
    for (int i = 0; i < q; ++i) cout << ans[i] << '\n';
}

Compilation message (stderr)

election.cpp:2: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    2 | #pragma GCC optimization ("O3")
      | 
election.cpp:3: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    3 | #pragma GCC optimization ("unroll-loops")
      | 
election.cpp: In member function 'void SegmentTree::add(int, int, int, int, int, int)':
election.cpp:36:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   36 |         int mid = L + R >> 1;
      |                   ~~^~~
election.cpp: In member function 'int SegmentTree::get(int, int, int, int, int)':
election.cpp:47:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   47 |         int mid = L + R >> 1;
      |                   ~~^~~
election.cpp: In function 'int main()':
election.cpp:86:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   86 |     for (auto [u, v, i]: work) {
      |               ^
election.cpp:87:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   87 |         while (j < s.size() && s[j].first < u) {
      |                ~~^~~~~~~~~~

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