Submission #867109

#	Time	Username	Problem	Language	Result	Execution time	Memory
867109		Ahmed_Solyman	The short shank; Redemption (BOI21_prison)	C++14	35 / 100	2082 ms	62544 KiB

prison

/*
In the name of Allah
made by: Ahmed_Solyman
*/
#include <bits/stdc++.h>
#include <ext/rope>
 
using namespace std;
using namespace __gnu_cxx;
#pragma GCC optimize("-Ofast")
#pragma GCC optimize("-O1")
//-------------------------------------------------------------//
typedef long long ll;
typedef unsigned long long ull;
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define PI acos(-1)
#define lb lower_bound
#define ub upper_bound
#define endl '\n'
#define all(v) v.begin(),v.end()
#define allr(v) v.rbegin(),v.rend()
#define sum_to(n) (n*(n+1))/2
#define pb push_back
#define pf push_front
#define fil(arr,x) memset(arr,x,sizeof(arr))
const ll mod=1e9+7;
int dx[8]={0,1,0,-1,1,1,-1,-1};
int dy[8]={1,0,-1,0,1,-1,-1,1};
//-------------------------------------------------------------//
ll lcm(ll a,ll b)
{
    return (max(a,b)/__gcd(a,b))*min(a,b);
}
void person_bool(bool x)
{
    cout<<(x?"YES":"NO")<<endl;
}
const int N=4005;
int dp[N][2];
int cost[N][N];
int n,k,t;
void solve(int l,int r,int i,int j,int g){
	if(l>r){
		return ;
	}
	int mid=l+r>>1;
	dp[mid][g]=1e9;
	int opt=i;
	for(int k=i;k<=min(j,mid);k++){
        if((k?dp[k-1][g^1]:1e9)+cost[k][mid]<dp[mid][g]){
            opt=k;
            dp[mid][g]=(k?dp[k-1][g^1]:1e9)+cost[k][mid];
        }
    }
    solve(l,mid-1,i,opt,g);
    solve(mid+1,r,opt,j,g);
}
int main()
{
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    #ifndef ONLINE_JUDGE
    //freopen("input.in", "r", stdin);
    //freopen("output.out", "w", stdout);
    #endif
    fast
    cin>>n>>k>>t;
    vector<int>arr(n);
    for(auto &i:arr)cin>>i;
    for(int i=0;i<n;i++){
    	stack<int>s;
    	for(int j=i;j<n;j++){
    		int x=1e9;
    		if(s.size())x=s.top();
    		s.push(min(arr[j],x+1));
    		if(i==j) cost[i][j]=(s.top()<=t);
    		else cost[i][j]=cost[i][j-1]+(s.top()<=t);
    	}
    	dp[i][0]=cost[0][i];
    }
    for(int i=1;i<=k;i++){
    	solve(0,n-1,0,n-1,i%2);
    }
    cout<<dp[n-1][k%2]<<endl;
    return 0;
}

Compilation message (stderr)

prison.cpp: In function 'void solve(int, int, int, int, int)':
prison.cpp:46:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   46 |  int mid=l+r>>1;
      |          ~^~

• Subtask 1: 15 / 15
• Subtask 2: 0 / 10
• Subtask 3: 20 / 20
• Subtask 4: 0 / 10
• Subtask 5: 0 / 25
• Subtask 6: 0 / 20