Submission #1247901

#	Time	Username	Problem	Language	Result	Execution time	Memory
1247901		free_de_la_zenith	K blocks (IZhO14_blocks)	C++20	100 / 100	117 ms	18404 KiB

blocks

/**
 *    author:  MINHTPC
 *
**/
#include <bits/stdc++.h>

#define ll long long
#define fi first
#define se second
#define pb push_back
#define all(a) a.begin() , a.end()
#define FOR(i ,a , b) for(int i = a ; i <= b ; ++i)
#define bit(mask,i) ((mask>>i)&1)
#define name "task"
#define lo lower_bound
#define up upper_bound
#define count_bit1(x) __builtin_popcountll(x)
#define count_bit01(x) __builtin_clzll(x)
#define count_bit10(x) __builtin_ctzll(x)

using namespace std;
const int N=1e6+5;
const long long INF=1e18;
using pii=pair<ll,ll>;
long long a[N],dp[N],f[N],L[N];
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    if(fopen("umnik.inp","r")) {
        freopen("umnik.inp","r",stdin);
//        freopen("umnik.out","w",stdout);
    }
    int n,k;
    cin >> n >> k;
    for(int i=1;i<=n;i++) cin >> a[i];
    stack<int>s;
    for(int i=1;i<=n;i++) {
        while(!s.empty() && a[s.top()]<=a[i]) s.pop();
        L[i]=s.empty()?1:s.top()+1;
        s.push(i);
    }
    memset(f,60,sizeof f);
    memset(dp,60,sizeof dp);
    f[1]=a[1];
    for(int i=2;i<=n;i++) f[i]=max(f[i-1],a[i]);
    for(int j=2;j<=k;j++) {
        stack<pii>st;
        for(int i=1;i<=n;i++) {
            dp[i]=dp[L[i]-1];
            long long mn=f[i-1];
            while(!st.empty() && st.top().se<=a[i]) {
                mn=min(mn,st.top().fi);
                st.pop();
            }
            dp[i]=min(dp[i],mn+a[i]);
            st.push({mn,a[i]});
        }
        for(int i=1;i<=n;i++) {
            f[i]=dp[i];
            dp[i]=INF;
        }
    }
    cout << f[n];
}

Compilation message (stderr)

blocks.cpp: In function 'int main()':
blocks.cpp:31:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |         freopen("umnik.inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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