Submission #1291971

#	Time	Username	Problem	Language	Result	Execution time	Memory
1291971		thaibeo123	Foehn Phenomena (JOI17_foehn_phenomena)	C++20	100 / 100	96 ms	6480 KiB

foehn_phenomena

#include <bits/stdc++.h>
using namespace std;

#define NAME "A"
#define ll long long
#define fi first
#define se second
#define pb push_back
#define all(x) x.begin(), x.end()
#define MASK(x) (1ll << (x))
#define BIT(x, i) (((x) >> (i)) & 1)

const int N = 2e5 + 5;

struct FenwickTree {
    int n;
    vector<ll> fen;

    FenwickTree() {}
    FenwickTree(int n): n(n), fen(n + 5) {}

    void update(int x, int v) {
        for (int i = x; i <= n; i += i & -i) {
            fen[i] += v;
        }
    }

    ll get(int x) {
        ll res = 0;
        for (int i = x; i > 0; i -= i & -i) {
            res += fen[i];
        }
        return res;
    }
};
FenwickTree fen;

int n, q;
ll s, t;
int a[N];

ll compute(int x, int y) {
    if (y > n) return 0;
    ll ans = 0;
    ll one = a[x] + fen.get(x), two = a[y] + fen.get(y);
    if (one < two) {
        ans += s * (two - one);
    }
    else {
        ans += t * (one - two);
    }
    return ans;
}

void input() {
    cin >> n >> q >> s >> t;
    s = -s;
    for (int i = 0; i <= n; i++) {
        cin >> a[i];
    }
}

void solve() {
    fen = FenwickTree(n);
    ll ans = 0;
    for (int i = 1; i <= n; i++) {
        if (a[i - 1] < a[i]) {
            ans += s * (a[i] - a[i - 1]);
        }
        else {
            ans += t * (a[i - 1] - a[i]);
        }
    }
    while (q--) {
        int l, r, x;
        cin >> l >> r >> x;
        ans -= compute(l - 1, l);
        ans -= compute(r, r + 1);
        fen.update(l, x);
        fen.update(r + 1, -x);
        ans += compute(l - 1, l);
        ans += compute(r, r + 1);
        cout << ans << "\n";
    }
}

signed main() {
    if (fopen(NAME".INP", "r")) {
        freopen(NAME".INP", "r", stdin);
        freopen(NAME".OUT", "w", stdout);
    }
    cin.tie(0)->sync_with_stdio(0);

    int t = 1;
    //cin >> t;
    while (t--) {
        input();
        solve();
    }

    return 0;
}

Compilation message (stderr)

foehn_phenomena.cpp: In function 'int main()':
foehn_phenomena.cpp:89:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |         freopen(NAME".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
foehn_phenomena.cpp:90:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |         freopen(NAME".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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