Submission #968255

#	Time	Username	Problem	Language	Result	Execution time	Memory
968255		phoenix0423	Real Mountains (CCO23_day1problem2)	C++17	0 / 25	4 ms	6616 KiB

Main

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pll;
#define fastio ios::sync_with_stdio(false), cin.tie(0)
#pragma GCC optimize("Ofast")
#define pb push_back
#define eb emplace_back
#define f first
#define s second
#define int long long
#define lowbit(x) x&-x
const int maxn = 1e6 + 1;
const int N = 1e6 + 3;
const int INF = 1e18;
int h[maxn], l[maxn], r[maxn], cl[maxn], cr[maxn];

signed main(void){
    fastio;
    int n;
    cin>>n;
    int mn = 0;
    for(int i = 0; i < n; i++){
        cin>>h[i];
        if(h[i] < h[mn]) mn = i;
    }
    for(int i = mn; i > 0; i--) assert(h[i - 1] >= h[i]);
    for(int i = mn; i < n - 1; i++) assert(h[i + 1] >= h[i]);
    for(int i = 0; i < n; i++) r[i] = -1;
    for(int i = 0; i < n; i++){
        l[i] = r[i] = -1;
        for(int j = i - 1; j >= 0; j--){
            if(h[j] > h[i]){
                l[i] = j;
                break;
            }
        }
        for(int j = i + 1; j < n; j++){
            if(h[j] >= h[i]){
                r[i] = j;
                break;
            }
        }
    }
    // stack<int> st;
    // for(int i = 0; i < n; i++){
    //     while(!st.empty() && h[st.top()] <= h[i]){
    //         r[st.top()] = i;
    //         st.pop();
    //     }
    //     if(st.empty()) l[i] = -1;
    //     else l[i] = st.top();
    //     st.push(i);
    // }
    // for(int i = n - 1; i >= 0; i--){
    //     while(r[i] != -1 && h[r[i]] == h[i]) r[i] = r[r[i]];
    // }
    int ans = 0;
    for(int i = 1; i < n; i++){
        if(r[i] == -1 || l[i] == -1) continue;
        if(h[r[i]] == h[i]) continue;
        int cnt = r[i] - l[i] - 1;
        int dif = min(h[r[i]], h[l[i]]) - h[i];
        // cout<<i<<" "<<cnt<<" "<<dif<<"\n";
        // cout<<h[l[i]]<<" "<<h[r[i]]<<"\n";
        ans += dif * (h[l[i]] + h[i] + h[r[i]]) + dif * (dif - 1) / 2;
        if(cnt >= 2)
            ans += dif * (min(h[l[i]], h[r[i]]) + h[i] * 2) + dif * (dif + 1) - dif;
        if(cnt > 2)
            ans += (cnt - 2) * (dif * h[i] * 3 + dif * (dif + 1) + dif * (dif - 1) / 2);
        // cout<<"ans : "<<ans<<"\n";
    }
    cout<<ans<<"\n";
    return 0;
    vector<pll> e;
    for(int i = 0; i < n; i++) e.eb(h[i], i);
    sort(e.begin(), e.end());
    for(auto [hei, id] : e){
        // cout<<"cur : "<<id<<" "<<hei<<"\n";
        // cout<<l[id]<<" "<<r[id]<<"\n";
        if(l[id] == -1 || r[id] == -1) continue;
        if(h[r[id]] == h[id]){
            cl[r[id]] += cl[id] + cr[id] + 1;
            continue;
        }
        int dif = min(h[l[id]] - h[id], h[r[id]] - h[id]);
        // cout<<"dif : "<<dif<<"\n";
        // cout<<cl[id]<<" "<<cr[id]<<"\n";
        ans += dif * (h[l[id]] + h[id] + h[r[id]]) + dif * (dif - 1) / 2;
        // cout<<"tmp : "<<ans<<"\n";
        // cout<<dif<<" * "<<min(h[l[id]], h[r[id]])<<" "<<h[id] * 2<<"\n";
        ans += (cl[id] + cr[id]) * (dif * (min(h[l[id]], h[r[id]]) + h[id] * 2) + dif * (dif + 1) - dif);
        // ans += cr[id] * (dif * (h[r[id]] + h[id] * 2) + dif * (dif + 1) - dif);
        if(h[l[id]] < h[r[id]]){
            cr[l[id]] += cl[id] + cr[id] + 1;
        }
        else{
            cl[r[id]] += cl[id] + cr[id] + 1;
        }
        // cout<<"res : "<<ans<<"\n";
    }
    cout<<ans<<"\n";
}

• Subtask 1: 0 / 3
• Subtask 2: 0 / 3
• Subtask 3: 0 / 3
• Subtask 4: 0 / 3
• Subtask 5: 0 / 4
• Subtask 6: 0 / 5
• Subtask 7: 0 / 4