Submission #950223

#	Time	Username	Problem	Language	Result	Execution time	Memory
950223		vjudge1	Sjeckanje (COCI21_sjeckanje)	C++17	55 / 110	2035 ms	6340 KiB

Main

#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
 
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define int long long
#define rnd(l, r) uniform_int_distribution<int>(l, r)(rng)
 
using namespace std;

void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);} 
int pow(int a,int b,int m){int ans=1;while(b){if(b&1){ans=(ans*a)%m;}b>>=1;a=(a*a)%m;}return ans;}
int binpow(int a,int b){int ans=1;while(b){if(b&1){ans=(ans*a);}b>>=1;a=(a*a);}return ans;}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
 
const int N = 2e5 + 10, MX = 2e5 + 10, inf = 1e18;

int a[N], dp[N];

int n;
struct st{
	int mx = -inf, mn = inf, dpcost = 0, ans = 0;
	
};

st t[N * 4];

int bmn[N * 4], bmx[N * 4], used[N * 4];

st merge(st a, st b){
	st res;
	res.ans = max(a.ans, b.ans);
	res.ans = max(a.ans + a.mx - a.mn, b.ans + b.mx - b.mn);
	return res;
}

void push(int v, int tl, int tr) {
	if(!used[v]) return;
	t[v].mn = min(t[v].mn, bmn[v]);
	t[v].mx = max(t[v].mx, bmx[v]);
	t[v].ans = max(t[v].ans, t[v].dpcost + t[v].mx - t[v].mn);
	if (tl != tr) {
		bmx[v * 2] = max(bmx[v * 2], bmx[v]);
		bmx[v * 2 + 1] = max(bmx[v * 2 + 1], bmx[v]);
		bmn[v * 2] = min(bmn[v * 2], bmn[v]);
		bmn[v * 2 + 1] = min(bmn[v * 2 + 1], bmn[v]);
		
		used[v * 2 + 1] = 1;
		used[v * 2] = 1;
	}
	used[v]=0;
}
void update2(int pos, int x, int v = 1,int tl = 1, int tr = n){
	push(v, tl, tr);
    if(tl == tr){
        t[v].ans = x;
       // t[v].ans = t[v].dpcost + t[v].mx - t[v].mn;
    }else{
        int mid = (tl + tr) >> 1;
        if(pos <= mid)
			update2(pos, x, v * 2, tl, mid);
        else
			update2(pos, x, v * 2 + 1,mid + 1, tr);
		t[v] = merge(t[v * 2], t[v * 2 + 1]);
    }
}
void update(int l, int r, int x, int v = 1, int tl = 1, int tr = n){
	push(v, tl, tr);
	if (tr < l || r < tl) return;
	if(l <= tl && tr <= r){
		bmn[v] = min(bmn[v], x);
		bmx[v] = max(bmx[v], x);
		used[v]=1;
		push(v, tl, tr);
		return;
 	}else{	
		push(v, tl, tr);
		int mid=(tl+tr)/2;
		update(l, r, x,  v * 2, tl, mid);
		update(l, r, x,  v * 2 + 1, mid + 1, tr);
	}
}
 
int get(int l, int r, int v = 1, int tl = 1, int tr = n){
    if(tl > r || tr < l)
        return 0;
    if(tl >= l && tr <= r){
        return t[v].ans;
    }
    int mid = (tl + tr) >> 1;	
    return max(get(l, r, v * 2, tl, mid),get(l, r, v * 2 + 1, mid + 1, tr));
}

main(){
	iostream::sync_with_stdio(false);	
    cin.tie(nullptr);
    cout.tie(nullptr);
	int q;
	cin >> n >> q;
	for(int i = 1; i <= n; i++){
		cin >> a[i];
	}
	while(q--){
		int l, r, x;
		cin >> l >> r >> x;
		for(int i = l; i <= r; i++){
			a[i] += x;
		}
		for(int i = 1; i <= n; i++)dp[i] = -inf;
		int mn = -inf, mx = -inf;
		for(int i = 1; i <= n; i++){
			mn = max(dp[i - 1] - a[i], mn);
			mx = max(dp[i - 1] + a[i], mx);
			dp[i] = max(mx - a[i], mn + a[i]);
			dp[i] = max(dp[i - 1], dp[i]);
			//cout << dp[i] <<"-";
		}
		cout << dp[n] << endl;
	}
	//cout << ans << endl;
}	
/*
 * Before implementing the problem:
	
	Do I understand the problem correctly?
	Which places are tricky? What do I need to remember to implement them correctly?
	Which place is the heaviest by implementation? Can I do it simpler?
	Which place is the slowest? Where do I need to be careful about constant factors and where I can choose slower but simpler implementation?
	----------------------------------
	If not AC:
 
	Did you remember to do everything to handle the tricky places you thought about before?
	Is the solution correct?
	Do I understand the problem correctly?
	----------------------------------
	If you have a test on which the solution gives wrong answer:
 
	Is the solution doing what it was supposed to do?
	Is the problem in the code or in the idea?
*/

Compilation message (stderr)

Main.cpp:98:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   98 | main(){
      | ^~~~
Main.cpp: In function 'void fp(std::string)':
Main.cpp:15:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 | void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:15:70: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 | void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                                                               ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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