Submission #1123432

#	Time	Username	Problem	Language	Result	Execution time	Memory
1123432		zNatsumi	K blocks (IZhO14_blocks)	C++20	100 / 100	207 ms	3084 KiB

blocks

#include <bits/stdc++.h>

using namespace std;

#define int long long
const int N = 1e5 + 5,
          INF = 1e16;

int n, k, a[N], dp[2][N];

int32_t main(){
  cin.tie(0)->sync_with_stdio(0);
  #define task "blocks"
  if(fopen(task ".inp", "r")){
    freopen(task ".inp", "r", stdin);
    freopen(task ".out", "w", stdout);
  }
  cin >> n >> k;
  for(int i = 1; i <= n; i++) cin >> a[i];

  for(int i = 0; i <= n; i++) dp[0][i] = dp[1][i] = INF;
  dp[0][0] = 0;

  for(int j = 1; j <= k; j++){
    stack<int> st;
    for(int i = 1; i <= n; i++){
      dp[1][i] = dp[0][i - 1] + a[i];
      while(st.size() && a[st.top()] <= a[i]){
        if(dp[0][st.top()] != INF) dp[1][i] = min(dp[1][i], dp[0][st.top()] + a[i]);
        if(dp[1][st.top()] != INF) dp[1][i] = min(dp[1][i], dp[1][st.top()] - a[st.top()] + a[i]);
        st.pop();
      }
      if(st.size()){
        if(dp[1][st.top()] != INF) dp[1][i] = min(dp[1][i], dp[1][st.top()]);
        if(dp[0][st.top()] != INF) dp[1][i] = min(dp[1][i], dp[0][st.top()] + a[i]);
        if(dp[0][st.top() - 1] != INF) dp[1][i] = min(dp[1][i], dp[0][st.top() - 1] + a[st.top()]);
      }
      else if(j == 1) dp[1][i] = a[i];
      st.push(i);
    }
    for(int i = 0; i <= n; i++){
      dp[0][i] = dp[1][i];
      dp[1][i] = INF;
    }
  }
  cout << dp[0][n];

  return 0;
}

Compilation message (stderr)

blocks.cpp: In function 'int32_t main()':
blocks.cpp:15:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     freopen(task ".inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
blocks.cpp:16:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |     freopen(task ".out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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