Submission #681219

#	Time	Username	Problem	Language	Result	Execution time	Memory
681219		Tien_Noob	Election (BOI18_election)	C++17	100 / 100	827 ms	50120 KiB

election

//Make CSP great again
//Vengeance
#include <bits/stdc++.h>
#define TASK "TESTCODE"
using namespace std;
const int N = 5e5 + 1;
int n, q, res[N + 1];
int pref[N + 1], suf[N + 1], a[N + 1];
vector<pair<int, int> > query[N + 1];
struct SegmentTree
{
    int tree[4 * N + 1], lazy[4 * N + 1];
    void buildtree(int v, int TreeL, int TreeR)
    {
        if (TreeL == TreeR)
        {
            tree[v] = suf[TreeL];
            return ;
        }
        int mid = (TreeL + TreeR)/2;
        buildtree(v * 2, TreeL, mid);
        buildtree(v * 2 + 1, mid + 1, TreeR);
        tree[v] = min(tree[2 * v], tree[2 * v + 1]);
    }
    void push(int v)
    {
        if (!lazy[v])
        {
            return ;
        }
        int d = lazy[v];
        lazy[v] = 0;
        lazy[2 * v] += d;
        lazy[2 * v + 1] += d;
        tree[2 * v] += d;
        tree[2 * v + 1] += d;
    }
    void add(int v, int TreeL, int TreeR, int L, int R, int val)
    {
        if (L > R)
        {
            return ;
        }
        if (TreeL == L && TreeR == R)
        {
            tree[v] += val;
            lazy[v] += val;
            return ;
        }
        int mid = (TreeL + TreeR)/2;
        push(v);
        add(v * 2, TreeL, mid, L, min(R, mid), val);
        add(v * 2 + 1, mid + 1, TreeR, max(L, mid + 1), R, val);
        tree[v] = min(tree[2 * v], tree[2 * v + 1]);
    }
    int get(int v, int TreeL, int TreeR, int L, int R)
    {
        if (L > R)
        {
            return 1e9;
        }
        if (TreeL == L && TreeR == R)
        {
            return tree[v];
        }
        int mid = (TreeL + TreeR)/2;
        push(v);
        return min(get(v * 2, TreeL, mid, L, min(R, mid)), get(v * 2 + 1, mid + 1, TreeR, max(L, mid + 1), R));
    }
} tree;
void read()
{
    cin >> n;
    for (int i = 1; i <= n; ++ i)
    {
        char c;
        cin >> c;
        a[i] = (c == 'C' ? 1 : -1);
        pref[i] = pref[i - 1] + a[i];
    }
    for (int i = n; i >= 1; -- i)
    {
        suf[i] = suf[i + 1] + a[i];
    }
    tree.buildtree(1, 1, n + 1);
}
void solve()
{
    cin >> q;
    for (int i = 1; i <= q; ++ i)
    {
        int l, r;
        cin >> l >> r;
        query[l].emplace_back(r, i);
    }
    vector<int> st;
    for (int l = n; l >= 0; -- l)
    {
        while(!st.empty() && pref[l] <= pref[st.back()])
        {
            tree.add(1, 1, n + 1, 1, st.back(), -1);
            st.pop_back();
        }
        for (auto [r, i] : query[l + 1])
        {
            res[i] += upper_bound(st.rbegin(), st.rend(), r) - st.rbegin();
            int t = tree.get(1, 1, n + 1, l + 1, r) - tree.get(1, 1, n + 1, r + 1, r + 1);
            res[i] += max(0, -t);
        }
        st.push_back(l);
        tree.add(1, 1, n + 1, 1, l, 1);
    }
    for (int i = 1; i <= q; ++ i)
    {
        cout << res[i] << '\n';
    }
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    if (fopen(TASK".INP", "r"))
    {
        freopen(TASK".INP", "r", stdin);
        //freopen(TASK".OUT", "w", stdout);
    }
    int t = 1;
    bool typetest = false;
    if (typetest)
    {
        cin >> t;
    }
    for (int __ = 1; __ <= t; ++ __)
    {
        //cout << "Case " << __ << ": ";
        read();
        solve();
    }
}

Compilation message (stderr)

election.cpp: In function 'int main()':
election.cpp:124:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  124 |         freopen(TASK".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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