Submission #1016037

#	Time	Username	Problem	Language	Result	Execution time	Memory
1016037		ngothecuong07	K blocks (IZhO14_blocks)	C++14	100 / 100	167 ms	84680 KiB

blocks

#include<bits/stdc++.h>

#define int long long
#define pi pair<int, int>

using namespace std;

const int N = 1e5 + 5,
          K = 1e2 + 5,
          INF = 1e17;

int n, k;
int a[N];
int f[N][K];

signed main() {
  cin.tie(0)->sync_with_stdio(0);
  if(fopen("task.inp", "r")) {
    freopen("task.inp", "r", stdin);
    freopen("task.out", "w", stdout);
  }
  if(fopen("KBLOCK.inp", "r")) {
    freopen("KBLOCK.inp", "r", stdin);
    freopen("KBLOCK.out", "w", stdout);
  }

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

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

  f[1][1] = a[1];
  for(int i = 2; i <= n; ++i) f[i][1] = max(f[i - 1][1], a[i]);

  for(int j = 2; j <= k; ++j) {
    stack<pi> st;

    for(int i = j; i <= n; ++i) {
      int mi = f[i - 1][j - 1];
      while(st.size() && a[st.top().first] <= a[i]) {
        mi = min(mi, st.top().second);
        st.pop();
      }
      f[i][j] = min(f[st.size() ? st.top().first : 0][j], mi + a[i]);
      st.push({i, mi});
    }
  }

  cout << f[n][k];
}

Compilation message (stderr)

blocks.cpp: In function 'int main()':
blocks.cpp:19:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |     freopen("task.inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
blocks.cpp:20:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |     freopen("task.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
blocks.cpp:23:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |     freopen("KBLOCK.inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
blocks.cpp:24:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 |     freopen("KBLOCK.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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