Submission #406280

#	Time	Username	Problem	Language	Result	Execution time	Memory
406280		arujbansal	Discharging (NOI20_discharging)	C++17	20 / 100	290 ms	16068 KiB

Discharging

    #include <bits/stdc++.h>
    using namespace std;
    #define int long long
     
    const int inf = 1e15;
    const int N = 1502;
     
    template<typename T> 
    struct li_chao_min {
        static const T identity = numeric_limits<T>::max();
    
        struct Line {
            T m, c;
    
            Line() {
                m = 0;
                c = identity;
            }
    
            Line(T m, T c) : m(m), c(c) {}
    
            T val(T x) { return m * x + c; }
        };
    
        struct Node {
            Line line;
            Node *lc, *rc;
    
            Node() : lc(0), rc(0) {}        
        };
    
        T L, R, eps;
        deque<Node> buffer;
        Node* root;
    
        Node* new_node() {
            buffer.emplace_back();
            return &buffer.back();
        }
    
        li_chao_min() {}
    
        li_chao_min(T _L, T _R, T _eps) {
            init(_L, _R, _eps);
        }
    
        void init(T _L, T _R, T _eps) {
            L = _L;
            R = _R;
            eps = _eps;
    
            root = new_node();
        }
    
        void insert(Node* &cur, T l, T r, Line line) {
            if (!cur) {
                cur = new_node();
                cur->line = line;
                return;
            }
    
            T mid = l + (r - l) / 2;
            if (r - l <= eps) return;
    
            if (line.val(mid) < cur->line.val(mid))
                swap(line, cur->line);
    
            if (line.val(l) < cur->line.val(l)) insert(cur->lc, l, mid, line);
            else insert(cur->rc, mid + 1, r, line);
        }
    
        T query(Node* &cur, T l, T r, T x) {
            if (!cur) return identity;
    
            T mid = l + (r - l) / 2;
            T res = cur->line.val(x);
            if (r - l <= eps) return res;
    
            if (x <= mid) return min(res, query(cur->lc, l, mid, x));
            else return min(res, query(cur->rc, mid + 1, r, x));
        }
    
        void insert(T m, T c) { insert(root, L, R, Line(m, c)); }
    
        T query(T x) { return query(root, L, R, x); }
    };
     
    signed main() {
        std::ios::sync_with_stdio(0);
        std::cout.tie(0);
        std::cin.tie(0);
        int n; cin >> n;
        vector<int> a(n + 1), dp(n + 1);
        for(int i = 1; i <= n; i++) cin >> a[i];
        li_chao_min<int> lct(0, 1000000, 0);
        dp[1] = a[1] * n;
        lct.insert(n, 0); //querying all n at one time
        int mx = a[1];
        for(int i = 2; i <= n; i++) {
            mx = max(mx, a[i]);
            lct.insert(n - i + 1, dp[i - 1]);
            dp[i] = lct.query(mx);
            //we can qry for mx cuz the x coordinate has to be atleast mx (all under same time mx)
        }
        cout << dp[n] << '\n';
        return 0;
    }

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