Submission #284870

#	Time	Username	Problem	Language	Result	Execution time	Memory
284870		achibasadzishvili	Discharging (NOI20_discharging)	C++14	36 / 100	1100 ms	239704 KiB

Discharging

#include<bits/stdc++.h>
#define ll long long
#define f first
#define s second
#define pb push_back
using namespace std;
ll n,a[1000002],dp[1000002],rm[1000002][21],po[2000002],pw[200];
vector<ll>del[1000002];
set<ll>st;
set<ll>::iterator it;
ll get(ll x,ll y){
    ll lo = po[y - x + 1];
    return max(rm[y][lo] , rm[x + pw[lo] - 1][lo]);
}
ll ind(ll x,ll y){
    if(y == n)return -1;
    ll l = y + 1,r = n,mid,ind = -1;
    while(r >= l){
        mid = (l + r) / 2;
        if(dp[x] + get(x + 1 , mid) * (n - x) >= dp[y] + get(y + 1 , mid) * (n - y)){
            r = mid - 1;
            ind = mid;
        }
        else
            l = mid + 1;
    }
    return ind;
}
void delet(ll x){
    if(st.find(x) == st.end())return;
    if(st.find(x) == st.begin()){
        st.erase(st.begin());
        return;
    }
    if(st.upper_bound(x) == st.end()){
        st.erase(st.find(x));
        return;
    }
    st.erase(st.find(x));
    it = st.upper_bound(x);
    ll y = (*it);
    it--;
    x = (*it);
    ll cur = ind(x , y);
    if(cur == -1)return;
    del[cur].pb(x);
}
int main(){
    ios::sync_with_stdio(false);
    cin >> n;
    
    for(int i=1; i<=n; i++){
        cin >> a[i];
    }
    
    pw[0] = 1;
    
    for(int i=1; i<=21; i++){
        pw[i] = pw[i - 1] * 2;
        for(int j=pw[i - 1]; j<pw[i]; j++){
            if(j <= 1000000)
                po[j] = i - 1;
        }
    }
    
    for(int i=1; i<=n; i++){
        rm[i][0] = a[i];
        for(int j=1; j<=20; j++){
            if(i - pw[j] + 1 >= 1)
                rm[i][j] = max(rm[i][j - 1] , rm[i - pw[j - 1]][j - 1]);
        }
    }
    
    st.insert(0);
    
    for(int i=1; i<=n; i++){
        for(int j=0; j<del[i].size(); j++){
            delet(del[i][j]);
        }
        ll x = (*st.begin());
        dp[i] = dp[x] + get(x + 1 , i) * (n - x);
        it = st.end();
        it--;
        st.insert(i);
        ll cur = ind((*it) , i);
        if(cur != -1)
            del[cur].pb((*it));
    }
    
    cout << dp[n];
    
    
    return 0;
}

Compilation message (stderr)

Discharging.cpp: In function 'int main()':
Discharging.cpp:77:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   77 |         for(int j=0; j<del[i].size(); j++){
      |                      ~^~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 13 / 13
• Subtask 3: 0 / 25
• Subtask 4: 0 / 11
• Subtask 5: 14 / 14
• Subtask 6: 0 / 28