Submission #404345

#	Time	Username	Problem	Language	Result	Execution time	Memory
404345		AmineWeslati	Cigle (COI21_cigle)	C++14	100 / 100	417 ms	196548 KiB

cigle

//Never stop trying
#include "bits/stdc++.h"
using namespace std;
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)

typedef long long ll;
typedef string str;
typedef long double ld;
typedef pair<int, int> pi;
#define fi first
#define se second
typedef vector<int> vi;
typedef vector<pi> vpi;
#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define endl "\n"
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)

const int MOD = 1e9 + 7; //998244353
const ll INF = 1e9;
const int nx[4] = {0, 0, 1, -1}, ny[4] = {1, -1, 0, 0}; //right left down up

template<class T> using V = vector<T>;
template<class T> bool ckmin(T& a, const T& b) { return a > b ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up
//constexpr int log2(int x) { return 31 - __builtin_clz(x); } // floor(log2(x))

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
//mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
ll random(ll a, ll b){
    return a + rng() % (b - a + 1);
}
#ifndef LOCAL  
#define cerr if(false) cerr
#endif
#define dbg(x) cerr << #x << " : " << x << endl; 
#define dbgs(x,y) cerr << #x << " : " << x << " / " << #y << " : " << y << endl;
#define dbgv(v) cerr << #v << " : " << "[ "; for(auto it : v) cerr << it << ' '; cerr << ']' << endl;
#define here() cerr << "here" << endl;

void IO() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin); 
    freopen("output.txt", "w", stdout);
#endif
}
/////////////////////////ONLY CLEAN CODES ALLOWED/////////////////////////

const int MX=5e3+10;
int N; 

/*vector<vi>t(MX,vi(MX*4,0));

void upd(int idx, int i, int v, int pos=1, int l=0, int r=N-1){
	if(l==r){
		t[idx][pos]=v;
		return; 
	}

	int m=(l+r)/2;
	if(i<=m) upd(idx,i,v,pos*2,l,m);
	else upd(idx,i,v,pos*2+1,m+1,r);

	t[idx][pos]=max(t[idx][pos*2],t[idx][pos*2+1]);
}

int get(int idx, int l, int r, int pos=1, int tl=0, int tr=N-1){
	if(l>r) return 0;
	if(l==tl && r==tr) return t[idx][pos];

	int tm=(tl+tr)/2;
	return max( get(idx,l,min(r,tm),pos*2,tl,tm), 
		get(idx,max(l,tm+1),r,pos*2+1,tm+1,tr));
}*/

int main() {
    boost; IO();

    cin>>N;
    vi a(N);
    FOR(i,0,N) cin>>a[i];

    vector<vi>dp(N,vi(N,0)),pref(N,vi(N,0));

    FOR(l,1,N){
    	int l2=l,cur=0,prev=0,v=0;
    	FOR(r,l,N){
    		cur+=a[r];

    		while(l2 && prev<cur-a[r]){
    			l2--;
    			prev+=a[l2];
    		}
    		if(l2 && prev==cur-a[r]){
    			if(prev) v++;
    			l2--; 
    			prev+=a[l2];
    		}

    		dp[l][r]=pref[l-1][l2]+v;
    		if(l!=r) ckmax(dp[l][r],dp[l][r-1]);

    		ckmax(pref[r][l],dp[l][r]);

    		//upd(r,l,dp[l][r]);
    	}

    	int rgt=l;
    	FOR(lft,0,rgt+1){
    		pref[rgt][lft]=dp[lft][rgt];
    		if(lft) ckmax(pref[rgt][lft],pref[rgt][lft-1]);
    	}

    }

    int ans=0;
    FOR(i,0,N) ckmax(ans,dp[i][N-1]);
    cout << ans << endl;

    

    return 0;
}
//Change your approach 

• Subtask 1: 9 / 9
• Subtask 2: 11 / 11
• Subtask 3: 13 / 13
• Subtask 4: 15 / 15
• Subtask 5: 52 / 52