Submission #837573

#	Time	Username	Problem	Language	Result	Execution time	Memory
837573		borisAngelov	Foehn Phenomena (JOI17_foehn_phenomena)	C++17	100 / 100	205 ms	14708 KiB

foehn_phenomena

#include <bits/stdc++.h>

using namespace std;

const int maxn = 200005;

int n, q;
long long s, t;

int a[maxn];
long long delta[maxn];

struct state
{
    long long positive_sum; // multiply by s
    long long negative_sum; // multiply by t
};

struct segment_tree
{
    state tree[4 * maxn];

    state combine(const state left_child, const state right_child)
    {
        state result;

        result.positive_sum = left_child.positive_sum + right_child.positive_sum;
        result.negative_sum = left_child.negative_sum + right_child.negative_sum;

        return result;
    }

    void build(int node, int l, int r)
    {
        if (l == r)
        {
            if (delta[l] < 0)
            {
                tree[node].negative_sum = delta[l];
                tree[node].positive_sum = 0;
            }
            else
            {
                tree[node].positive_sum = delta[l];
                tree[node].negative_sum = 0;
            }

            return;
        }

        int mid = (l + r) / 2;

        build(2 * node, l, mid);
        build(2 * node + 1, mid + 1, r);

        tree[node] = combine(tree[2 * node], tree[2 * node + 1]);
    }

    void update(int node, int l, int r, int pos, long long val)
    {
        if (l == r)
        {
            if (val < 0)
            {
                tree[node].negative_sum = val;
                tree[node].positive_sum = 0;
            }
            else
            {
                tree[node].positive_sum = val;
                tree[node].negative_sum = 0;
            }

            return;
        }

        int mid = (l + r) / 2;

        if (pos <= mid)
        {
            update(2 * node, l, mid, pos, val);
        }
        else
        {
            update(2 * node + 1, mid + 1, r, pos, val);
        }

        tree[node] = combine(tree[2 * node], tree[2 * node + 1]);
    }

    void build()
    {
        build(1, 1, n);
    }

    void update(int pos, long long val)
    {
        update(1, 1, n, pos, val);
    }
};

segment_tree tree;

void fastIO()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

int main()
{
    fastIO();

    cin >> n >> q >> s >> t;

    for (int i = 1; i <= n + 1; ++i)
    {
        cin >> a[i];
    }

    for (int i = 1; i <= n; ++i)
    {
        delta[i] = a[i] - a[i + 1];
    }

    tree.build();

    for (int i = 1; i <= q; ++i)
    {
        int l, r, val;
        cin >> l >> r >> val;

        if (l != 0)
        {
            delta[l] -= val;
            tree.update(l, delta[l]);
        }

        if (r != n)
        {
            delta[r + 1] += val;
            tree.update(r + 1, delta[r + 1]);
        }

        cout << tree.tree[1].negative_sum * s + tree.tree[1].positive_sum * t << "\n";
    }

    return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 10 / 10
• Subtask 3: 60 / 60