Submission #783136

#	Time	Username	Problem	Language	Result	Execution time	Memory
783136		pera	Exam (eJOI20_exam)	C++17	0 / 100	1 ms	468 KiB

exam

#include<bits/stdc++.h>
using namespace std;

#define int long long

const int N = 2e5 + 1;


main(){
	ios::sync_with_stdio(0);
	cin.tie(0),cout.tie(0);
	int n , oK = 1;cin >> n;
	vector<int> a(n + 1) , b(n + 1);
	for(int i = 1;i <= n;i ++){
		cin >> a[i];
	}
	for(int i = 1;i <= n;i ++){
		cin >> b[i];
		if(i != 1) oK &= (b[i] == b[i - 1]);
	}
	if(oK){
		int c = 0 , C = 0 , ok = 0;
		for(int i = 1;i <= n;i ++){
			if(a[i] > b[i]){
				if(ok) c += C;
				C = 0;
				continue;
			}
			if(a[i] == b[i]) ok = 1;
			++ C;
		}
		if(ok) c += C;
		cout << c << endl;
	}else{
		oK = 1;
		for(int i = 2;i <= n;i ++){
			oK &= (a[i] > a[i - 1]);
		}
		if(oK){
			vector<int> dp(n + 1);
			vector<vector<int>> c(n + 1 , vector<int>(n + 1));
			for(int i = 1;i <= n;i ++){
				for(int j = 1;j <= n;j ++){
					c[i][j] = c[i][j - 1] + (b[j] == a[i]);
				}
			}
			dp[1] = (a[1] == b[1]);
			for(int i = 2;i <= n;i ++){
				for(int j = 1;j < i;j ++){
					dp[i] = max(dp[i] , dp[j] + c[i][i] - c[i][j - 1]);
				}
			}
			cout << dp[n] << endl;
		}
	}
}

Compilation message (stderr)

exam.cpp:9:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
    9 | main(){
      | ^~~~

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