Submission #990071

#	Time	Username	Problem	Language	Result	Execution time	Memory
990071		HuyAT	Sjeckanje (COCI21_sjeckanje)	C++14	55 / 110	2025 ms	10300 KiB

Main

#include<bits/stdc++.h>
#define newl '\n'

const int N = 2e5 + 10;
const int V = 1e7 + 10;
const long long INF = 1e18;
const long long M = 1e9 + 7;

long long a[N + 1],b[N + 1];
int n,q;
long long diff[N + 1],f[N + 1];

void readData(){
    std::cin >> n >> q;
    for(int i = 1;i <= n;++i){
        std::cin >> a[i];
        if(i > 1){
            diff[i - 1] = a[i] - a[i - 1];
        }
    }
}
long long calc(){
    std::vector<long long> b;
    b.emplace_back(0);
    b.emplace_back(a[1]);
    int it = 2;
    for(int i = 2;i < n;++i){
        if((a[i - 1] <= a[i]) != (a[i] <= a[i + 1])){
//            std::cerr << i << newl;4
            it = std::max(it,i - 1);
            while(it <= std::min(n,i + 1)){
                b.emplace_back(a[it]);
                ++it;
            }
        }
    }
    it = std::max(it,n);
    while(it <= n){
        b.emplace_back(a[it++]);
    }
//    for(int val : b){
//        std::cout << val << " ";
//    }
//    std::cout << newl;
    for(int i = 1;i < (int)b.size();++i){
        f[i] = 0;
        long long mx = b[i],mn = b[i];
        for(int j = i;j >= 1 && i - j + 1 <= 4;--j){
            mx = std::max(mx,(long long)b[j]);
            mn = std::min(mn,(long long)b[j]);
            f[i] = std::max(f[i],f[j - 1] + mx - mn);
        }
    }
    return f[(int)b.size() - 1];
}
void update(long long &ans,int i,int x){
    if(i > 1 && i < n){
        if((diff[i - 1] < 0) != (diff[i] < 0)){
            ans += std::min(abs(diff[i - 1]),abs(diff[i]));
        }
    }
    if(i < n - 1){
        if((diff[i] < 0) != (diff[i + 1] < 0)){
            ans += std::min(abs(diff[i]),abs(diff[i + 1]));
        }
    }
    if(i < n && i > 0){
        ans -= abs(diff[i]);
    }
    diff[i] += x;
    if(i < n && i > 0){
        ans += abs(diff[i]);
    }
    if(i > 1 && i < n){
        if((diff[i - 1] < 0) != (diff[i] < 0)){
            ans -= std::min(abs(diff[i - 1]),abs(diff[i]));
        }
    }
    if(i < n - 1){
        if((diff[i] < 0) != (diff[i + 1] < 0)){
            ans -= std::min(abs(diff[i]),abs(diff[i + 1]));
        }
    }
}
void solve(){
    long long ans = 0;
    for(int i = 1;i < n;++i){
        if(i < n - 1 && (diff[i] < 0) != (diff[i + 1] < 0)){
            ans -= std::min(abs(diff[i]),abs(diff[i + 1]));
        }
        ans += abs(diff[i]);
    }
//    std::cout << ans << newl;
    for(int i = 1;i <= q;++i){
        int l,r,x;
        std::cin >> l >> r >> x;
        for(int j = l;j <= r;++j){
            a[j] += x;
        }
//        update(ans,l - 1,x);
//        update(ans,r,-x);
//        assert(calc() == ans);
        std::cout << calc() << newl;
    }
}
int main(){
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);std::cout.tie(nullptr);
    readData();
    solve();
    return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 40 / 40
• Subtask 3: 0 / 55