Submission #941158

#	Time	Username	Problem	Language	Result	Execution time	Memory
941158		peterandvoi	Railway Trip 2 (JOI22_ho_t4)	C++17	100 / 100	613 ms	71176 KiB

Main

#include <bits/stdc++.h>

using namespace std;

#ifdef ngu
#include "debug.h"
#else
#define debug(...) 42
#endif

const int N = (int) 1e5 + 5;
const int LOG = 18;

int n, k, m, q;
pair<int, int> st[LOG][N];
int a[N << 1], b[N << 1];
vector<int> in[N], out[N];

struct segment_tree {
    int n;
    vector<pair<int, int>> tree;

    segment_tree() {};

    segment_tree(int n): n(n) {
        tree.resize(4 << __lg(n));
    }

    pair<int, int> cmb(pair<int, int> a, pair<int, int> b) {
        return {min(a.first, b.first), max(a.second, b.second)};
    }

    void upd(int i, pair<int, int> v) {
        int id = 1, l = 1, r = n;
        while (l < r) {
            int mid = l + r >> 1;
            id <<= 1;
            if (i <= mid) {
                r = mid;
            } else {
                l = mid + 1;
                id |= 1;
            }
        }
        tree[id] = v;
        while (id > 1) {
            id >>= 1;
            tree[id] = cmb(tree[id << 1], tree[id << 1 | 1]);
        }
    }

    pair<int, int> get(int u, int v, int id, int l, int r) {
        if (u <= l && r <= v) {
            return tree[id];
        }
        int mid = l + r >> 1;
        if (u <= mid && mid < v) {
            return cmb(get(u, v, id << 1, l, mid), get(u, v, id << 1 | 1, mid + 1, r));
        }
        if (mid < u) {
            return get(u, v, id << 1 | 1, mid + 1, r);
        }
        return get(u, v, id << 1, l, mid);
    }

    pair<int, int> get(int l, int r) {
        return get(l, r, 1, 1, n);
    }
};

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    #ifdef ngu
    freopen("test.inp", "r", stdin);
    freopen("test.out", "w", stdout);
    #endif
    cin >> n >> k >> m;
    vector<int> inc, dec;
    for (int i = 1; i <= m; ++i) {
        cin >> a[i] >> b[i];
        (a[i] < b[i] ? inc : dec).emplace_back(i);
    }
    for (int i : inc) {
        in[a[i]].emplace_back(b[i]);
        out[min(b[i] - 1, a[i] + k - 1)].emplace_back(b[i]);
    }
    multiset<int> s;
    for (int i = 1; i <= n; ++i) {
        st[0][i] = {i, i};
        for (int r : in[i]) {
            s.insert(r);
        }
        if (s.size()) {
            st[0][i].second = *s.rbegin();
        }
        for (int r : out[i]) {
            s.erase(s.find(r));
        }
        in[i].clear();
        out[i].clear();
    }
    s.clear();
    for (int i : dec) {
        in[a[i]].emplace_back(b[i]);
        out[max(b[i] + 1, a[i] - k + 1)].emplace_back(b[i]);
    }
    for (int i = n; i >= 1; --i) {
        for (int l : in[i]) {
            s.insert(l);
        }
        if (s.size()) {
            st[0][i].first = *s.begin();
        }
        for (int l : out[i]) {
            s.erase(s.find(l));
        }
    }
    vector<segment_tree> it(LOG);
    for (int i = 0; i < LOG; ++i) {
        it[i] = segment_tree(n);
    }
    for (int i = 1; i <= n; ++i) {
        it[0].upd(i, st[0][i]);
    }
    for (int j = 1; j < LOG; ++j) {
        for (int i = 1; i <= n; ++i) {
            st[j][i] = it[j - 1].get(st[j - 1][i].first, st[j - 1][i].second);
        }
        for (int i = 1; i <= n; ++i) {
            it[j].upd(i, st[j][i]);
        }
    }
    auto reach = [&](pair<int, int> x, int i) -> bool {
        return x.first <= i && i <= x.second;
    };
    cin >> q;
    while (q--) {
        int s, t;
        cin >> s >> t;
        if (reach(st[LOG - 1][s], t)) {
            pair<int, int> cur = {s, s};
            int res = 0;
            for (int i = LOG - 2; i >= 0; --i) {
                pair<int, int> new_cur = it[i].get(cur.first, cur.second);
                if (!reach(new_cur, t)) {
                    cur = new_cur;
                    res += 1 << i;
                }
            }
            cout << res + 1 << "\n";
        } else {
            cout << -1 << "\n";
        }
    }
}

Compilation message (stderr)

Main.cpp: In member function 'void segment_tree::upd(int, std::pair<int, int>)':
Main.cpp:36:25: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   36 |             int mid = l + r >> 1;
      |                       ~~^~~
Main.cpp: In member function 'std::pair<int, int> segment_tree::get(int, int, int, int, int)':
Main.cpp:56:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   56 |         int mid = l + r >> 1;
      |                   ~~^~~

• Subtask 1: 8 / 8
• Subtask 2: 8 / 8
• Subtask 3: 11 / 11
• Subtask 4: 25 / 25
• Subtask 5: 35 / 35
• Subtask 6: 13 / 13