Submission #1104298

#	Time	Username	Problem	Language	Result	Execution time	Memory
1104298		TrinhKhanhDung	Exam (eJOI20_exam)	C++14	36 / 100	72 ms	77896 KiB

exam

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define sz(x) (int)x.size()
#define ALL(v) v.begin(), v.end()
#define MASK(k) (1LL << (k))
#define BIT(x, i) (((x) >> (i)) & 1)
#define INF (ll)1e9
#define oo (ll)1e18
#define MOD (ll)(1e9 + 7)

using namespace std;

template<class T1, class T2>
    bool maximize(T1 &a, T2 b){if(a < b){a = b; return true;} return false;}

template<class T1, class T2>
    bool minimize(T1 &a, T2 b){if(a > b){a = b; return true;} return false;}

template<class T1, class T2>
    void add(T1 &a, T2 b){a += b; if(a >= MOD) a -= MOD;}

template<class T1, class T2>
    void sub(T1 &a, T2 b){a -= b; if(a < 0) a += MOD;}

template<class T>
    void cps(T &v){sort(ALL(v)); v.resize(unique(ALL(v)) - v.begin());}

const int MAX = 2e5 + 10;

int N;
int A[MAX], B[MAX], lef[MAX], rig[MAX];

void input(){
    cin >> N;
    for(int i = 1; i <= N; i++) cin >> A[i];
    for(int i = 1; i <= N; i++) cin >> B[i];
}

void compress(){
    vector<int> tmp;
    for(int i = 1; i <= N; i++) tmp.push_back(A[i]);
    for(int i = 1; i <= N; i++) tmp.push_back(B[i]);
    cps(tmp);
    for(int i = 1; i <= N; i++) A[i] = lower_bound(ALL(tmp), A[i]) - tmp.begin();
    for(int i = 1; i <= N; i++) B[i] = lower_bound(ALL(tmp), B[i]) - tmp.begin();
}

void setup(){
    for(int i = 1; i <= N; i++){
        lef[i] = i - 1;
        while(lef[i] > 0 && A[i] >= A[lef[i]]) lef[i] = lef[lef[i]];
    }
    for(int i = N; i >= 1; i--){
        rig[i] = i + 1;
        while(rig[i] <= N && A[i] >= A[rig[i]]) rig[i] = rig[rig[i]];
    }
}

namespace subtask2{
    void solve(){

    }
}

namespace subtask3{
    bool check(){
        for(int i = 2; i <= N; i++){
            if(A[i] <= A[i - 1]) return false;
        }
        return true;
    }

    const int MAX = 5003;

    int f[MAX][MAX];
    //f[i][j]: ap dung nhung thay doi tu A[1] -> A[i] cho nhung thang tu 1 -> j

    void solve(){
        int ans = 0;
        for(int i = 1; i <= N; i++){
            for(int j = 1; j <= i; j++){
                f[i][j] = max(f[i - 1][j], f[i][j - 1]);
                if(A[i] == B[j]){
                    maximize(f[i][j], f[i][j - 1] + 1);
                }
                maximize(ans, f[i][j]);
            }
        }

        cout << ans << '\n';
    }
}

namespace seg{
    int it[MAX * 4];
    int n;

    void init(int _n = 0){
        n = _n;
        memset(it, 0, n * 4 * sizeof(int));
    }

    void upd(int p, int c){
        int i = 1, l = 1, r = n;
        while(l < r){
            int m = (l + r) >> 1;
            if(p <= m){
                i = i * 2;
                r = m;
            }
            else{
                i = i * 2 + 1;
                l = m + 1;
            }
        }
        maximize(it[i], c);
        while(i > 1){
            i >>= 1;
            it[i] = max(it[i * 2], it[i * 2 + 1]);
        }
    }

    int get(int u, int v, int i = 1, int l = 1, int r = n){
        if(r < u || v < l) return 0;
        if(u <= l && r <= v) return it[i];
        int m = (l + r) >> 1;
        return max(get(u, v, i * 2, l, m), get(u, v, i * 2 + 1, m + 1, r));
    }
}

namespace subtask4{
    bool check(){
        vector<int> tmp;
        for(int i = 1; i <= N; i++) tmp.push_back(A[i]);
        cps(tmp);
        return sz(tmp) == N;
    }

    int pos[MAX];

    void solve(){
        seg::init(N);

        for(int i = 1; i <= N; i++){
            pos[A[i]] = i;
        }

        for(int i = 1; i <= N; i++){
            int p = pos[B[i]];
            if(p == 0) continue;
            if(lef[p] < i && i < rig[p]){
                seg::upd(p, seg::get(1, p) + 1);
            }
        }

        cout << seg::it[1] << '\n';
    }
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
//    freopen("creature.inp", "r", stdin);
//    freopen("creature.out", "w", stdout);

    input();
    compress();
    setup();

    if(subtask3::check()) return subtask3::solve(), 0;
    if(subtask4::check()) return subtask4::solve(), 0;

    return 0;
}

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