Submission #615401

#TimeUsernameProblemLanguageResultExecution timeMemory
615401HediChehaidarTriple Jump (JOI19_jumps)C++17
19 / 100
2903 ms205740 KiB
#include<bits/stdc++.h>
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef double db;
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;} // greatest common divisor (PGCD)
ll lcm(ll a , ll b) {return (a * b) / gcd(a , b);} // least common multiple (PPCM)
#define ss second
#define ff first
#define all(x) (x).begin() , (x).end()
#define pb push_back
#define vi vector<int>
#define vii vector<pair<int,int>>
#define vl vector<ll>
#define vll vector<pair<ll,ll>>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pdd  pair<double,double>
#define vdd  vector<pdd>
#define dte  tuple<double , double , double>
using namespace std;
const int INF = 1000*1000*1000; // 1 e 9
const int MOD = 1e9 + 7;//998244353 ;
const double EPS = 0.000000001; // 1 e -9
const ll inf = (ll)1e18;

int n;
int st[(int)2e6 + 10];
ll v[(int)2e6 + 10];
void build(int pos , int l , int r){
    if(l == r){
        st[pos] = v[l]; return;
    }
    build(2 * pos + 1 , l , (l+r) / 2 ); build(2 * pos + 2 , (l+r) / 2 + 1 , r);
    st[pos] = max(st[2 * pos + 1] , st[2 * pos + 2]);
}
int rq(int pos , int l  ,int r , int i  ,int j){
    if(i > r || j < l) return 0;
    if(i <= l && j >= r) return st[pos];
    return max(rq(2 * pos + 1 , l , (l+r) / 2 , i , j) , rq(2 * pos + 2 , (l+r) / 2 + 1 , r , i, j ));
}
ll dp[5050][5050];
ll solve(int l  ,int r){
    if(r - l == 2) return v[l] + v[r] + v[l + 1];
    if(dp[l][r] != -1) return dp[l][r];
    ll ans = v[l] + v[r] + rq(0 , 0 , n - 1 , l + 1 , l + (r - l) / 2);
    return dp[l][r] = max(ans , max(solve(l + 1 , r) , solve(l , r - 1)));
}

int main(){
    //ifstream fin ("testing.txt");
    //ofstream fout ("output.txt");
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    cin>>n;
    if(n > 5000) return 0;
    for(int i = 0 ; i < n ; i++) cin>>v[i];
    int q; cin>>q;
    build(0 , 0 , n - 1);
    memset(dp , -1 , sizeof dp);
    while(q--){
        int  l , r; cin>>l>>r; l--,r--;
        cout << solve(l , r) << "\n";
    }
    return 0;
}

/*
    Think of : BS / DFS / BFS / SSSP / SCC / MSP / MAX FLOW / TOPSORT / LCA / MATRIX / DP(bitmask) / 2 POINTERS / SEG TREE / MATH / UN FIND / MO / HLD
    Read the statement CAREFULLY !!
    Make a GREADY APPROACH !!!! (start from highest / lowest)
    Make your own TESTS !!
    Be careful from CORNER CASES !
*/
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