Submission #501930

#	Time	Username	Problem	Language	Result	Execution time	Memory
501930		nighty	Hedgehog Daniyar and Algorithms (IZhO19_sortbooks)	C++14	77 / 100	3035 ms	38632 KiB

sortbooks

#include <bits/stdc++.h>

using namespace std;

int calcMaxInv(vector<int>& a, int l, int r) {
    int maxVal = 0, res = 0;
    for (int i = l; i <= r; ++i) {
        if (maxVal > a[i]) {
            res = max(res, maxVal + a[i]);
        }
        maxVal = max(maxVal, a[i]);
    }
    return res;
}

const int K = 470;
const int N = 1e6;

vector<int> s[N / K + 10];
int maxInverse[N / K + 10];

int calcMaxInv2(vector<int>& a, int l, int r) {
    int res = 0, maxVal = 0;
    if (l % K != 0) {
        res = calcMaxInv(a, l, min(r, l - l % K + K - 1));
        maxVal = *max_element(a.begin() + l, a.begin() + l - l % K + K - 1 + 1);
        l = l - l % K + K;
    }
    while (l + K - 1 <= r) {
        res = max(res, maxInverse[l / K]);
        auto it = lower_bound(s[l / K].begin(), s[l / K].end(), maxVal);
        if (it != s[l / K].begin()) {
            --it;
            res = max(res, *it + maxVal);
        }
        maxVal = max(maxVal, *s[l / K].rbegin());
        l += K;
    }
    if (l <= r) {
        for (int i = l; i <= r; ++i) {
            if (a[i] < maxVal) {
                res = max(res, a[i] + maxVal);
            }
        }
        res = max(res, calcMaxInv(a, l, r));
    }
    return res;
}

const int INF = 2e9;

struct segtree {
    int n;
    struct node {
        int min, max;
        bool isSorted;

        friend node combine(node a, node b) {
            if (!a.isSorted || !b.isSorted) {
                return {std::min(a.min, b.min), std::max(a.max, b.max), false};
            }
            if (a.max <= b.min) {
                return {std::min(a.min, b.min), std::max(a.max, b.max), true};
            }
            return {std::min(a.min, b.min), std::max(a.max, b.max), false};
        }
    };
    vector<node> tree;

    void build(vector<int>& a) {
        n = 1;
        while (n < a.size()) {
            n *= 2;
        }
        tree.assign(n * 2, {INF, -INF, true});
        for (int i = 0; i < a.size(); ++i) {
            tree[n - 1 + i] = {a[i], a[i], true};
        }
        for (int i = n - 2; i >= 0; --i) {
            tree[i] = combine(tree[2 * i + 1], tree[2 * i + 2]);
        }
    }

    node get(int l, int r, int x, int lx, int rx) {
        if (rx < l || r < lx) {
            return {INF, -INF, true};
        }
        if (l <= lx && rx <= r) {
            return tree[x];
        }
        node a = get(l, r, x * 2 + 1, lx, (lx + rx) / 2);
        node b = get(l, r, x * 2 + 2, (lx + rx) / 2 + 1, rx);
        return combine(a, b);
    }

    node get(int l, int r) {
        return get(l, r, 0, 0, n - 1);
    }
};

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n, m;
    cin >> n >> m;
    vector<int> a(n);
    for (auto& i : a) {
        cin >> i;
    }
    for (int i = 0; i < n; ++i) {
        s[i / K].push_back(a[i]);
    }
    for (auto& i : s) {
        sort(i.begin(), i.end());
    }
    for (int i = 0; (i + 1) * K - 1 < n; ++i) {
        maxInverse[i] = calcMaxInv(a, i * K, (i + 1) * K - 1);
    }
    int minVal = *min_element(a.begin(), a.end());
    segtree st;
    st.build(a);
    while (m--) {
        int l, r, k;
        cin >> l >> r >> k;
        --l, --r;
        if (k < minVal) {
            cout << st.get(l, r).isSorted << '\n';
//            cout << is_sorted(a.begin() + l, a.begin() + r + 1) << '\n';
        } else {
            cout << (calcMaxInv2(a, l, r) <= k) << '\n';
        }
    }
    return 0;
}

Compilation message (stderr)

sortbooks.cpp: In member function 'void segtree::build(std::vector<int>&)':
sortbooks.cpp:72:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |         while (n < a.size()) {
      |                ~~^~~~~~~~~~
sortbooks.cpp:76:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |         for (int i = 0; i < a.size(); ++i) {
      |                         ~~^~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 9 / 9
• Subtask 3: 13 / 13
• Subtask 4: 17 / 17
• Subtask 5: 30 / 30
• Subtask 6: 0 / 23