Submission #1295691

#	Time	Username	Problem	Language	Result	Execution time	Memory
1295691		nguyenkhangninh99	Triple Jump (JOI19_jumps)	C++20	19 / 100	555 ms	397460 KiB

jumps

#include <bits/stdc++.h>
using namespace std;

#define int long long
const int maxn = 5e5 + 5;
int st[4 * maxn], val[maxn], lazy[maxn], a[maxn];
void build(int id, int l, int r){
    if(l == r) val[id] = a[l];
    else{
        int mid = (l + r) / 2;
        build(id * 2, l, mid);
        build(id * 2 + 1, mid + 1, r);
        val[id] = max(val[id * 2], val[id * 2 + 1]);
    }
}
void down(int id){
    lazy[id * 2] = max(lazy[id * 2], lazy[id]);
    lazy[id * 2 + 1] = max(lazy[id * 2 + 1], lazy[id]);
    st[id * 2] = max(st[id * 2], lazy[id] + val[id * 2]);
    st[id * 2 + 1] = max(st[id * 2 + 1], lazy[id] + val[id * 2 + 1]);
    lazy[id] = 0;
}
void update(int id, int l, int r, int u, int v, int x){
    if(l > v || r < u) return;
    if(u <= l && r <= v){
        lazy[id] = max(lazy[id], x);
        st[id] = max(st[id], val[id] + x);
        return;
    }

    down(id);
    int mid = (l + r) / 2;
    update(id * 2, l, mid, u, v, x);
    update(id * 2 + 1, mid + 1, r, u, v, x);
    st[id] = max(st[id * 2], st[id * 2 + 1]);
}

int get(int id, int l, int r, int u, int v){
    if(l > v || r < u) return 0;
    if(u <= l && r <= v) return st[id];

    down(id);
    int mid = (l + r) / 2;
    return max(get(id * 2, l, mid, u, v), get(id * 2 + 1, mid + 1, r, u, v));
}
void solve(){
    int n; cin >> n;
    for(int i = 1; i <= n; i++) cin >> a[i];

    int q; cin >> q;

    if(n <= 100 && q <= 100){
        while(q--){
            int l, r; cin >> l >> r;
            int ans = 0;
            for(int i = l; i <= r; i++){
                for(int j = i + 1; j <= r; j++){
                    for(int k = j + 1; k <= r; k++){
                        if(k - j >= j - i){
                            ans = max(ans, a[i] + a[j] + a[k]);
                        }
                    }
                }
            }
            cout << ans << "\n";
        }
    }else if(n <= 5000){
        vector<vector<int>> mx(n + 1, vector<int>(n + 1)), dp(n + 1, vector<int>(n + 1));
        for(int i = 1; i <= n; i++){
            mx[i][i] = a[i];
            for(int j = i + 1; j <= n; j++) mx[i][j] = max(mx[i][j - 1], a[j]);
        }

        for(int len = 2; len <= n - 1; len++){
            for(int i = 1; i + len <= n; i++){
                int j = i + len;
                int mid = (i + j) / 2;
                int L = max(1ll, i + 1), R = min(mid, j - 1);
                dp[i][j] = a[i] + mx[L][R] + a[j];
                dp[i][j] = max({dp[i][j], dp[i + 1][j], dp[i][j - 1]});
            }
        }

        while(q--){
            int l, r; cin >> l >> r;
            cout << dp[l][r] << "\n";
        }
    }else{
        //nhận xét với cặp i, j. thì max[i + 1, j - 1] < min(a[i], a[j]); tìm k trên suffix max
        //đẩy lên segment tree
        stack<int> s;

        vector<vector<pair<int, int>>> qry(n + 1);
        vector<vector<int>> at(n + 1);
        vector<int> ans(q + 1);
        for(int i = 1; i <= n; i++){
            while(!s.empty() && a[s.top()] <= a[i]){
                at[s.top()].push_back(i);
                s.pop();
            }
            if(!s.empty()) at[s.top()].push_back(i);
            s.push(i);
        }

        for(int i = 1; i <= q; i++){
            int l, r; cin >> l >> r;
            qry[l].push_back({r, i});
        }

        build(1, 1, n);
        for(int i = n; i >= 1; i--){
            for(auto j: at[i]) if(2 * j - i <= n) update(1, 1, n, 2 * j - i, n, a[i] + a[j]);
            for(auto [r, id]: qry[i]) ans[id] = get(1, 1, n, i, r);
        }
        for(int i = 1; i <= q; i++) cout << ans[i] << "\n";
    }
}
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
  
    solve();
}
 

• Subtask 1: 5 / 5
• Subtask 2: 14 / 14
• Subtask 3: 0 / 27
• Subtask 4: 0 / 54