Submission #1198181

#	Time	Username	Problem	Language	Result	Execution time	Memory
1198181		dangheo	K blocks (IZhO14_blocks)	C++20	53 / 100	1098 ms	59268 KiB

blocks

#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <iomanip>
#include <numeric>
#include <stack>

#define hyathu main

using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pint = int*;

constexpr int mmb = 1e5 + 9, mmn = 4e5 + 69, mmk = 101;
const ld pi = atan(1) * 4;
const ld golden = (1+sqrtl(5))/2;

int n, k;
ll a[mmb], dp[mmk][mmb], l[mmb], r[mmb];
//li = so dau tien lon hon ai o ben trai
//ri = ...

struct SegTree{
    int n;
    ll st[mmn];
    
    void SetN(int N){
        n = N;
        fill(st + 1, st + 4 * n + 10, 9e18);
    }
    
    void DoUpdate(int l, int r, int id, const int &x, const ll &y){
        if(l > x || r < x) return;
        
        if(l == r){
            st[id] = min(st[id], y);
            return;
        }
        
        int mid = (l + r) / 2;
        DoUpdate(l, mid, id * 2, x, y);
        DoUpdate(mid + 1, r, id * 2 + 1, x, y);
        
        st[id] = min(st[id * 2], st[id * 2 + 1]);
    }
    
    inline void update(const int &x, const ll &y){
        DoUpdate(0, n + 1, 1, x, y);
    }
    
    ll Query(int l, int r, int id, int u, int v){
        if(l > v || r < u)
            return 9e18;
        
        if(u <= l && r <= v)
            return st[id];
        
        int mid = (l + r) / 2;
        return min(Query(l, mid, id * 2, u, v), Query(mid + 1, r, id * 2 + 1, u, v));
    }
    
    inline ll getMin(const int &x, const int &y){
        return Query(0, n + 1, 1, x, y);
    }
    
} segtree;

void readData(){
    cin >> n >> k;
    for(int i = 1; i <= n; ++i)
        cin >> a[i];
}

void prepareLR(){
    a[0] = a[n + 1] = 9e18;
    stack <int> st;
    st.push(0);
    for(int i = 1; i <= n; ++i){
        while(a[i] >= a[st.top()]) st.pop();
        l[i] = st.top();
        st.push(i);
    }
    while(!st.empty()) st.pop();
    st.push(n + 1);
    for(int i = n; i >= 1; --i){
        while(a[i] >= a[st.top()]) st.pop();
        r[i] = st.top();
        st.push(i);
    }
//    for(int i = 1; i <= n; ++i) cout << l[i] << " ";
//    cout << "\n";
//    for(int i = 1; i <= n; ++i) cout << r[i] << " ";
//    cout << "\n";
}

void solve(){
    prepareLR();
    
    //dp[j][i] = max(dp[j - 1][k] : (i > k & l[i] < r[k])
    // -> update(r[i], dp[j][i])
    //    getMin(l[i] + 1, n + 1)
    
    ll mx = -9e18;
    for(int i = 1; i <= n; ++i)
        dp[1][i] = mx = max(mx, a[i]);
    
    for(int j = 2; j <= k; ++j){
        segtree.SetN(n + 1);
        segtree.update(r[j - 1], dp[j - 1][j - 1]);
        for(int i = j; i <= n; ++i){
            dp[j][i] = segtree.getMin(l[i] + 1, n + 1) + a[i];
            segtree.update(r[i], dp[j - 1][i]);
        }
    }
    
//    for(int j = 1; j <= k; ++j){
//        for(int i = 1; i <= n; ++i){
//            if(dp[j][i] == 9e18) cout << "  * ";
//            else cout << setw(3) << dp[j][i] << " ";
//        }
//        cout << "\n";
//    }
    
    ll ans = 9e18;
    for(int i = k; i <= n; ++i)
        if(r[i] >= n + 1)
            ans = min(ans, dp[k][i]);
    cout << ans;
}

#define filename "test"

int hyathu(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    
    #ifdef dangheo
    freopen("test.inp", "r", stdin);
    //freopen("test.out", "w", stdout);
    #else
    //freopen(filename".INP", "r", stdin);
    //freopen(filename".OUT", "w", stdout);
    #endif
    
    readData();
    solve();
    
    return 0;
}

• Subtask 1: 14 / 14
• Subtask 2: 18 / 18
• Subtask 3: 21 / 21
• Subtask 4: 0 / 47