Submission #466246

#	Time	Username	Problem	Language	Result	Execution time	Memory
466246		idas	Exam (eJOI20_exam)	C++11	43 / 100	1087 ms	98516 KiB

exam

#include<bits/stdc++.h>
#define FOR(i, begin, end) for(int i=(begin); i<(end); i++)
#define FAST_IO ios_base::sync_with_stdio(false); cin.tie(nullptr)
#define PB push_back
#define F first
#define S second

const int INF=1e9;
const long long LINF=1e18;

using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef map<int, int> mii;

void setIO()
{
    FAST_IO;
}

void setIO (string s) {
    setIO();
 	freopen((s+".in").c_str(),"r",stdin);
 	freopen((s+".out").c_str(),"w",stdout);
}

const int N=5e3+10;
int n, a[N], b[N], t[2*N], dp[N][N];

void build()
{
    for(int i=n-1; i>=0; i--) t[i]=max(t[i<<1], t[i<<1|1]);
}

int get(int l, int r)
{
    int ret=0;
    for(l+=n, r+=n; l<r; l>>=1, r>>=1){
        if(l&1) ret=max(ret, t[l++]);
        if(r&1) ret=max(ret, t[--r]);
    }
    return ret;
}

int main()
{
    setIO();
    cin >> n;
    FOR(i, 0, n)
    {
        cin >> a[i+1];
        t[i+n]=a[i+1];
    }
    FOR(i, 0, n) cin >> b[i+1];
    build();

    FOR(i, 1, n+1)
    {
        FOR(j, 1, n+1)
        {
            if(a[i]==b[j]){
                int mx=get(min(i-1, j-1), max(i, j));
                if(mx==a[i]){
                    dp[i][j]=1;
                    dp[i][j]+=max(dp[i][j-1], dp[i-1][j-1]);
                }
                else{
                    dp[i][j]=max(max(dp[i-1][j], dp[i][j-1]), dp[i-1][j-1]);
                }
            }
            else{
                dp[i][j]=max(max(dp[i-1][j], dp[i][j-1]), dp[i-1][j-1]);
            }
        }
    }

    cout << dp[n][n];
}

Compilation message (stderr)

exam.cpp: In function 'void setIO(std::string)':
exam.cpp:24:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 |   freopen((s+".in").c_str(),"r",stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
exam.cpp:25:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   25 |   freopen((s+".out").c_str(),"w",stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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