Submission #1198210

#	Time	Username	Problem	Language	Result	Execution time	Memory
1198210		dangheo	K blocks (IZhO14_blocks)	C++20	100 / 100	317 ms	84304 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 FenwickTree{
    int n;
    ll ft[mmn];
    
    void SetN(int N){
        n = N;
        fill(ft + 1, ft + 4 * n + 10, 9e18);
    }
    
    inline void update(int x, const ll &y){
        ++x;
        for(int i = x; i <= n; i += (i & (-i)))
            ft[i] = min(ft[i], y);
    }
    
    ll getMin(int x){
        ++x;
        ll s = 9e18;
        for(int i = x; i > 0; i &= (i - 1))
            s = min(s, ft[i]);
        return s;
    }
    
} fentree;

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 & r[i] > l[k])
    // -> update(l[i], dp[j - 1][i])
    //    getMin(r[i] - 1)
    
    ll mx = -9e18;
    for(int i = n; i >= 1; --i)
        dp[1][i] = mx = max(mx, a[i]);
    
    for(int j = 2; j <= k; ++j){
        fentree.SetN(n + 1);
        fentree.update(l[n - j + 2], dp[j - 1][n - j + 2]);
        for(int i = n - j + 1; i > 0; --i){
            dp[j][i] = fentree.getMin(r[i] - 1) + a[i];
            fentree.update(l[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 = 1; i <= n - k + 1; ++i)
        if(l[i] <= 0)
            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: 47 / 47