Submission #1078688

#	Time	Username	Problem	Language	Result	Execution time	Memory
1078688		Tony_Tung	K blocks (IZhO14_blocks)	C++14	100 / 100	195 ms	84396 KiB

blocks

#include <bits/stdc++.h>
#define task "blocks"
#define int long long
using namespace std;

const int N = 1e5 + 5, K = 1e2 + 5, INF = 1e18;
int a[N], dp[N][K], n, k;
stack<int> st;

int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    if (fopen(task".in", "r"))
    {
        freopen(task".in", "r", stdin);
        freopen(task".out", "w", stdout);
    }

    cin >> n >> k;
    for (int i = 0; i <= n; i++)
        for (int j = 0; j <= k; j++) dp[i][j] = INF;

    for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
        dp[i][1] = (i == 1 ? a[i] : max(a[i], dp[i-1][1]));
    }

    for (int j = 2; j <= k; j++)
    {
        while (st.size()) st.pop();
        for (int i = 1; i <= n; i++)
        {
            while (st.size() && a[i] >= a[st.top()])
            {
                dp[i][j] = min(dp[i][j], min(dp[st.top()][j-1] + a[i], dp[st.top()][j] - a[st.top()] + a[i]));
                st.pop();
            }
            if (st.size())
                dp[i][j] = min(dp[i][j], min(dp[st.top()][j-1] + a[i], dp[st.top()][j]));
            st.push(i);
        }
    }
    cout << dp[n][k];

    return 0;
}

Compilation message (stderr)

blocks.cpp: In function 'int32_t main()':
blocks.cpp:16:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |         freopen(task".in", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
blocks.cpp:17:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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