Submission #1233403

#	Time	Username	Problem	Language	Result	Execution time	Memory
1233403		hoa208	K blocks (IZhO14_blocks)	C++20	100 / 100	106 ms	4448 KiB

blocks

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; i++)
#define FORD(i, b, a) for (int i = (b), _a = (a); i >= _a; i--)
#define pa pair<ll, ll>
#define fi first
#define se second
#define bit(mask, j) ((mask >> j) & 1)
#define t_test int t;cin >> t;while(t--)
const   ll mod = 1e9 + 7;
const   ll INF = 1e18;
inline  void adm(ll &x){if(x>=mod)x%=mod;else if(x<0)x+=mod;}
//--------------------------------------------------------------------
const ll N = 1e5 + 10;
const ll K = 102;
ll a[N];
ll f[N], g[N], L[N];
void hbmt() {
    ll n, k;
    cin >> n >> k;
    FOR(i ,1, n) {
        cin >> a[i];
    }
    stack<ll> st;
    FOR(i, 1, n) {
        while(!st.empty() && a[st.top()] <= a[i]) st.pop();
        if(st.empty()) L[i] = 1;
        else L[i] = st.top() + 1;
        st.push(i);
    }
    FOR(i, 0, n) f[i] = g[i] = INF;
    g[1] = a[1];
    FOR(i, 2, n) g[i] = max(g[i - 1], a[i]);
    FOR(j, 2, k) {
        stack<pa> st;
        FOR(i, 1, n) {
            f[i] = f[L[i] - 1];
            ll mn = g[i - 1];
            while(!st.empty() && st.top().se <= a[i]) {
                mn = min(mn, st.top().fi);
                st.pop();
            }
            f[i] = min(f[i], mn + a[i]);
            st.push({mn, a[i]});
        }
        FOR(i, 0, n) {
            g[i] = f[i];
            f[i] = INF;
        }
    }
    cout << g[n];
}

int main() {
    
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    
    if(fopen("hbmt.inp", "r")) {
        freopen("hbmt.inp", "r", stdin);
        freopen("hbmt.out", "w", stdout);
    }
    
    // t_test 
    hbmt();
    return 0;
}

Compilation message (stderr)

blocks.cpp: In function 'int main()':
blocks.cpp:61:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |         freopen("hbmt.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
blocks.cpp:62:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   62 |         freopen("hbmt.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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