Submission #951146

#	Time	Username	Problem	Language	Result	Execution time	Memory
951146		tnknguyen_	Foehn Phenomena (JOI17_foehn_phenomena)	C++14	100 / 100	135 ms	19540 KiB

foehn_phenomena

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n' 

const int sz = 2e5 + 5;
vector<int> qr[sz];
long long a[sz], d[sz];
int n, q, s, t;

// ------------ FUNCTIONS -----------
struct BIT{
    vector<int> f;
    int n = 2e5 + 5;

    BIT(){
        f.assign(n, 0);
    }

    void update(int i, int val){
        while(i < n){
            f[i] += val;
            i += (i & -i);
        }
    }

    int get(int i){
        int ans = 0;
        while(i > 0){
            ans += f[i];
            i -= (i & -i);
        }
        return ans;
    }
};

int cost(int x, int y){
    return (y > x ? -s*(y - x) : t*(x - y));
}

// ------------ SUBTASKS ------------
namespace SUB1{
    bool ok(){
        return (n <= 2000 && q <= 2000);
    }

    void solve(){
        for(int i=1; i<=q; ++i){
            int l = qr[i][0], r = qr[i][1], x = qr[i][2];
            int ans = 0;
            for(int j=1; j<=n; ++j){
                if(j >= l && j <= r){
                    a[j] += x;
                }
                if(a[j-1] < a[j]){
                    ans -= (a[j] - a[j-1])*s;
                }
                else{
                    ans += (a[j-1] - a[j])*t;
                }
            }
            cout<<ans<<endl;
        }

        //----------------------
        exit(0);
    }
}

namespace SUB23{
    void solve(){
        BIT bit;
        int ans = 0;
        for(int i=1; i<=n; ++i){
            bit.update(i, a[i]);
            bit.update(i+1, -a[i]);
            ans += cost(a[i-1], a[i]);
        }

        for(int i=1; i<=q; ++i){
            int l = qr[i][0], r = qr[i][1], x = qr[i][2];

            ans -= cost(bit.get(l-1), bit.get(l));
            bit.update(l, x);
            ans += cost(bit.get(l-1), bit.get(l));

            if(r + 1 <= n){
                ans -= cost(bit.get(r), bit.get(r+1));
                bit.update(r+1, -x);
                ans += cost(bit.get(r), bit.get(r+1));
            }
            cout<<ans<<endl;
        }

        //--------------------
        exit(0);
    }
}

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    //freopen("main.inp","r",stdin);
    //freopen("main.out","w",stdout);

    cin>>n>>q>>s>>t;
    for(int i=0; i<=n; ++i){
        cin>>a[i];
    }
    
    for(int i=1; i<=q; ++i){
        int l, r, x;
        cin>>l>>r>>x;
        qr[i] = {l, r, x};
    }

    if(SUB1::ok()){
        SUB1::solve();
        return 0;
    }
    SUB23::solve();

    return 0;
}

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