Submission #1091818

#	Time	Username	Problem	Language	Result	Execution time	Memory
1091818		underwaterkillerwhale	Split the sequence (APIO14_sequence)	C++17	0 / 100	2 ms	348 KiB

sequence

#include<bits/stdc++.h>
using namespace std;
#define all(fl) fl.begin(),fl.end()
#define pb push_back
#define fi first
#define se second
#define for1(i,j,k) for(int i=j;i<=k;i++)
#define for2(i,j,k) for(int i=j;i>=k;i--)
#define for3(i,j,k,l) for(int i=j;i<=k;i+=l)
#define lb lower_bound
#define ub upper_bound
#define sz(a) (int)a.size()
#define pii pair<int,int>
#define pli pair<long long,int>
#define gcd __gcd
#define lcm(x,y) x*y/__gcd(x,y)
const int maxn=2e3+9;
int a[maxn];
int f[maxn][maxn];
int mx[maxn][maxn];
int n,k;
int cal(int l,int r){
if (l>r)return 0;
if (f[l][r]!=-1)return f[l][r];
int pos=mx[l][r];//min pos
int ans=0;
for1(i,max(1,pos-k+1),min(pos,n-k+1)){//just <=n
int l1=max(i,l),r1=min(r,i+k-1);
ans=max(ans,cal(l,i-1)+cal(r1+1,r)+(r1-l1+1)*a[pos]);//dp to split into 2 array that min all array >=a[pos]
}
return f[l][r]=ans;
}
void sub4(){
    for1(i,1,n){
    mx[i][i]=i;
    for1(j,i+1,n){
    mx[i][j]=mx[i][j-1];
    if (a[j]<a[mx[i][j]])mx[i][j]=j;
    }
    }
    for1(i,1,n){
    for1(j,1,n){
    f[i][j]=-1;
    }
    }
    cout<<cal(1,n);
}
int dp[maxn];
void sub1(){
    for1(i,1,n)dp[i]=-1;
    for1(i,0,n-1){
    if (dp[i]<0)continue;
    for1(j,max(i+1-k+1,1),min(i+1,n-k+1)){
    dp[j+k-1]=max(dp[j+k-1],dp[i]+(j+k-1-i)*a[i+1]);
    }
    }
    cout<<dp[n];
    return;
}
void sub2(){
    for1(i,1,n)dp[i]=-1;
    for1(i,0,n-1){
    if (dp[i]<0)continue;
    if (a[i+1]==2){
    dp[i+1]=max(dp[i+1],dp[i]+2);
    }
    for1(j,i+1+k-1,n){
    dp[j]=max(dp[j],dp[i]+(j-(i+1)+1));
    }
    }
    cout<<dp[n];
}
signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    freopen("c.INP","r",stdin);
    freopen("c.ANS","w",stdout);
    cin>>n>>k;
    for1(i,1,n)cin>>a[i];
    bool fl=true;
    for1(i,1,n){
    if (a[i]<=2)continue;
    fl=false;
    break;
    }
    if (fl){
    sub2();
    return 0;
    }
    fl=true;
    for1(i,2,n){
    if (a[i-1]<=a[i])continue;
    fl=false;
    break;
    }
    if (fl){
    sub1();
    return 0;
    }
    sub4();
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:76:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |     freopen("c.INP","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~
sequence.cpp:77:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |     freopen("c.ANS","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 11
• Subtask 2: 0 / 11
• Subtask 3: 0 / 11
• Subtask 4: 0 / 17
• Subtask 5: 0 / 21
• Subtask 6: 0 / 29