Submission #463559

#	Time	Username	Problem	Language	Result	Execution time	Memory
463559		Kerim	Exam (eJOI20_exam)	C++17	88 / 100	227 ms	14896 KiB

exam

#include "bits/stdc++.h"
#define MAXN 200009
#define INF 1000000007
#define mp(x,y) make_pair(x,y)
#define all(v) v.begin(),v.end()
#define pb(x) push_back(x)
#define wr cout<<"----------------"<<endl;
#define ppb() pop_back()
#define tr(ii,c) for(__typeof((c).begin()) ii=(c).begin();ii!=(c).end();ii++)
#define ff first
#define ss second
#define my_little_dodge 46
#define debug(x)  cerr<< #x <<" = "<< x<<endl;
using namespace std;
 
typedef long long ll;
typedef pair<int,int> PII;
template<class T>bool umin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool umax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
int a[MAXN],b[MAXN],n,c,ans;
map<int,int>pm;
vector<int>adj[MAXN];
int F[MAXN],l[MAXN],r[MAXN];
void upd(int x,int val){
	for(;x<MAXN;x+=x&(-x))
		umax(F[x],val);
}
int tap(int x){
	int res=0;
	for(;x;x-=x&(-x))
		umax(res,F[x]);
	return res;
}
bool subtask2(){
	for(int i=1;i<=n;i++)
		if(b[i]!=b[1])
			return 0;
	return 1;
}
int main(){
    //~ freopen("file.in", "r", stdin);
    scanf("%d",&n);
    for(int i=1;i<=n;i++)	
		scanf("%d",a+i),pm[a[i]]=1;
	for(int i=1;i<=n;i++)
		scanf("%d",b+i),pm[b[i]]=1;
	a[0]=a[n+1]=INF;
	if(subtask2()){
		int st=1,ans=0;
		for(int i=1;i<=n+1;i++)
			if(a[i]>b[1]){
				ans+=i-st;
				st=i+1;
			}	
		printf("%d\n",ans);
		return 0;
	}
	tr(it,pm)it->ss=++c;
	stack<int>st;
	st.push(0);
	for(int i=1;i<=n;i++){
		while(!st.empty() and a[st.top()]<a[i])st.pop();
		l[i]=st.top();
		st.push(i);
	}
	while(!st.empty())st.pop();
	st.push(n+1);
	for(int i=n;i>=1;i--){
		while(!st.empty() and a[st.top()]<a[i])st.pop();
		r[i]=st.top();
		st.push(i);
	}
	for(int i=1;i<=n;i++)adj[pm[a[i]]].pb(i);
	for(int i=1;i<=n;i++){
		vector<int>&v=adj[pm[b[i]]];
		if(v.empty())continue;
		for(int ind=v.size()-1;ind>=0;ind--){
			int j=v[ind];
			if(i<=l[j] or r[j]<=i)continue;
			int dp=tap(j)+1;
			umax(ans,dp);
			upd(j,dp);
		}
	}
	printf("%d\n",ans);
	return 0;
}

Compilation message (stderr)

exam.cpp: In function 'int main()':
exam.cpp:42:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |     scanf("%d",&n);
      |     ~~~~~^~~~~~~~~
exam.cpp:44:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |   scanf("%d",a+i),pm[a[i]]=1;
      |   ~~~~~^~~~~~~~~~
exam.cpp:46:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |   scanf("%d",b+i),pm[b[i]]=1;
      |   ~~~~~^~~~~~~~~~

• Subtask 1: 14 / 14
• Subtask 2: 0 / 12
• Subtask 3: 13 / 13
• Subtask 4: 23 / 23
• Subtask 5: 16 / 16
• Subtask 6: 22 / 22