Submission #339947

#	Time	Username	Problem	Language	Result	Execution time	Memory
339947		Vladth11	Mountains (IOI17_mountains)	C++14	100 / 100	61 ms	23148 KiB

mountains

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define debug(x) cerr << #x << " " << x << "\n"
#define debug_with_space(x) cerr << #x << " " << x << " "
#include "mountains.h"
 
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef pair <ll, ll> pii;
typedef pair <ll, pii> piii;
typedef tree <pii, null_type, less <pii>, rb_tree_tag, tree_order_statistics_node_update> OST;
 
const ll NMAX = 2001;
const ll INF = (1LL << 60);
const ll MOD = 1000000007;
const ll BLOCK = 101;
const ll nr_of_bits = 35;
 
ll dp[NMAX][NMAX];
 
class ConvexHull{
    pii stiva[NMAX];
    ll vf;
    bool OK(pii a, pii b, pii c){
        return ((a.first * (b.second - c.second) + b.first * (c.second - a.second) + c.first * (a.second - b.second)) <= 0);
    }
public:
    ll size(){
        return vf;
    }
    void clear(){
        vf = 0;
    }
    ll last(){
        return stiva[vf].first;
    }
    ll lastbutone(){
        return stiva[vf - 1].first;
    }
    void push(pii x){
        while(vf > 1 && OK(stiva[vf], stiva[vf - 1], x)){
            vf--;
        }
        stiva[++vf] = x;
    }
}hull;
 
int maximum_deevs(vector<int> y) {
    ll i, j, maxim = 0;
    ll n = y.size();
    for(i = n; i >= 1; i--) {
        hull.clear();
        for(j = i; j <= n; j++) {
            hull.push({j, y[j - 1]});
            ll ultim = hull.last();
            dp[i][j] = 1;
            dp[i][j] = max(dp[i][j], dp[i][ultim - 1] + dp[ultim + 1][j]);
            if(hull.size() > 1) {
                ll penultim = hull.lastbutone();
                dp[i][j] = max(dp[i][j], dp[i][penultim - 1] + dp[penultim + 1][j]);
            }
            maxim = max(maxim, dp[i][j]);
        }
    }
    return maxim;
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 30 / 30