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Submission #809080

# Submission time Handle Problem Language Result Execution time Memory
809080 2023-08-05T15:49:28 Z AndrijaM Exam (eJOI20_exam) C++14
100 / 100
 228 ms 99572 KB 
#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <set>
#include <map>
#include <stack>
using namespace std;
typedef long long ll;
const int maxn = 1e5 + 10;
const int INF = 2e9;
int n;
int a[maxn], b[maxn];
int L[maxn], R[maxn];
int segment_tree[4 * maxn];
void solve_subtask2() {
    int x = b[0];
    int res = 0;
    for(int i = 0; i < n; i++) {
        if(a[i] == x) {
            res++;
            int j = i - 1;
            while(j >= 0 and a[j] <= x) {
                j--;
                res++;
            }
            j = i + 1;
            while(j < n and a[j] <= x) {
                res++;
                j++;
            }
            i = j - 1;
        }
    }
    cout << res << endl;
}
int dp[5005][5005];
int rec(int i, int j) {
    if(i < 0 or j < 0) {
        return 0;
    }
    if(dp[i][j] != -1) {
        return dp[i][j];
    }
    int res = 0;
    if(a[i] == b[j] and L[i] < j and R[i] > j) {
        res = max(res, rec(i, j - 1) + 1);
    }
    res = max(res, rec(i - 1, j));
    res = max(res, rec(i, j - 1));
    return dp[i][j] = res;
}
void build_tree(int L, int R, int node) {
    if(L == R) {
        segment_tree[node] = 0;
        return;
    }
    int middle = (L + R) / 2;
    build_tree(L, middle, 2 * node);
    build_tree(middle + 1, R, 2 * node + 1);
    segment_tree[node] = max(segment_tree[2 * node], segment_tree[2 * node + 1]);
}
int query(int i, int j, int L, int R, int node) {
    // L  R i L R j L R
    if(i <= L and R <= j) {
        return segment_tree[node];
    }
    if(R < i or j < L) {
        return 0;
    }
    int middle = (L + R) / 2;
    return max(query(i, j, L, middle, 2 * node), query(i, j, middle + 1, R, 2 * node + 1));
}
void update(int idx, int new_value, int L, int R, int node) {
    if(L == R) {
        segment_tree[node] = new_value;
        return;
    }
    int middle = (L + R) / 2;
    if(idx <= middle) {
        update(idx, new_value, L, middle, 2 * node);
    }
    else {
        update(idx, new_value, middle + 1, R, 2 * node + 1);
    }
    segment_tree[node] = max(segment_tree[2 * node], segment_tree[2 * node + 1]);
}
int main() {
    ios_base::sync_with_stdio(false);
    cin >> n;
    set<int> st;
    vector<int> t(n + 5);
    for(int i = 0; i < n; i++) {
        cin >> a[i];
        t[i + 1] = a[i];
    }
    for(int i = 0; i < n; i++) {
        cin >> b[i];
        st.insert(b[i]);
    }
    t[0] = INF;
    t[n + 1] = INF;
    stack<int> s;
    s.push(0);
    for(int i = 1; i <= n; i++) {
        while(t[s.top()] <= t[i]) {
            s.pop();
        }
        L[i - 1] = s.top() - 1;
        s.push(i);
    }
    while(!s.empty()) {
        s.pop();
    }
    s.push(n + 1);
    for(int i = n; i > 0; i--) {
        while(t[s.top()] <= t[i]) {
            s.pop();
        }
        R[i - 1] = s.top() - 1;
        s.push(i);
    }
    
    if((int) st.size() == 1) {
        solve_subtask2();
        return 0;
    }
    else if(n <= 5005){
        memset(dp, -1, sizeof dp);
        cout << rec(n - 1, n - 1) << endl;
    }
    else {
        build_tree(0, n - 1, 1);
        map<int, int> m;
        for(int i = 0; i < n; i++) {
            m[a[i]] = i;
        }
        
        for(int i = 0; i < n; i++) {
            map<int, int>::iterator it = m.find(b[i]);
            if(it != m.end()) {
                int idx = it->second;
                if(L[idx] < i and i < R[idx]) {
                    int dp = query(0, idx, 0, n - 1, 1);
                    update(idx, dp + 1, 0, n - 1, 1);
                }
            }
        }
        cout << query(0, n - 1, 0, n - 1, 1) << endl;
    }
    
    return 0;
}

Subtask #1
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 98252 KB Output is correct
2 Correct 35 ms 98296 KB Output is correct
3 Correct 34 ms 98368 KB Output is correct
4 Correct 32 ms 98352 KB Output is correct
5 Correct 33 ms 98252 KB Output is correct
6 Correct 33 ms 98324 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 6 ms 1108 KB Output is correct
3 Correct 13 ms 3608 KB Output is correct
4 Correct 10 ms 2592 KB Output is correct
5 Correct 20 ms 4308 KB Output is correct
6 Correct 12 ms 2644 KB Output is correct
7 Correct 13 ms 2808 KB Output is correct
8 Correct 19 ms 4168 KB Output is correct

Subtask #3
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 34 ms 98292 KB Output is correct
2 Correct 35 ms 98396 KB Output is correct
3 Correct 61 ms 98860 KB Output is correct
4 Correct 169 ms 99392 KB Output is correct
5 Correct 157 ms 99464 KB Output is correct
6 Correct 164 ms 99520 KB Output is correct

Subtask #4
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 171 ms 99496 KB Output is correct
2 Correct 28 ms 5392 KB Output is correct
3 Correct 80 ms 12136 KB Output is correct
4 Correct 82 ms 12912 KB Output is correct
5 Correct 95 ms 12240 KB Output is correct
6 Correct 88 ms 11536 KB Output is correct
7 Correct 83 ms 12492 KB Output is correct
8 Correct 72 ms 11532 KB Output is correct
9 Correct 86 ms 12292 KB Output is correct
10 Correct 64 ms 11944 KB Output is correct

Subtask #5
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 98252 KB Output is correct
2 Correct 35 ms 98296 KB Output is correct
3 Correct 34 ms 98368 KB Output is correct
4 Correct 32 ms 98352 KB Output is correct
5 Correct 33 ms 98252 KB Output is correct
6 Correct 33 ms 98324 KB Output is correct
7 Correct 34 ms 98308 KB Output is correct
8 Correct 35 ms 98364 KB Output is correct
9 Correct 37 ms 98380 KB Output is correct
10 Correct 35 ms 98388 KB Output is correct
11 Correct 35 ms 98340 KB Output is correct
12 Correct 34 ms 98376 KB Output is correct
13 Correct 34 ms 98372 KB Output is correct
14 Correct 34 ms 98332 KB Output is correct

Subtask #6
22.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 98252 KB Output is correct
2 Correct 35 ms 98296 KB Output is correct
3 Correct 34 ms 98368 KB Output is correct
4 Correct 32 ms 98352 KB Output is correct
5 Correct 33 ms 98252 KB Output is correct
6 Correct 33 ms 98324 KB Output is correct
7 Correct 34 ms 98292 KB Output is correct
8 Correct 35 ms 98396 KB Output is correct
9 Correct 61 ms 98860 KB Output is correct
10 Correct 169 ms 99392 KB Output is correct
11 Correct 157 ms 99464 KB Output is correct
12 Correct 164 ms 99520 KB Output is correct
13 Correct 34 ms 98308 KB Output is correct
14 Correct 35 ms 98364 KB Output is correct
15 Correct 37 ms 98380 KB Output is correct
16 Correct 35 ms 98388 KB Output is correct
17 Correct 35 ms 98340 KB Output is correct
18 Correct 34 ms 98376 KB Output is correct
19 Correct 34 ms 98372 KB Output is correct
20 Correct 34 ms 98332 KB Output is correct
21 Correct 34 ms 98348 KB Output is correct
22 Correct 40 ms 98508 KB Output is correct
23 Correct 1 ms 468 KB Output is correct
24 Correct 228 ms 99340 KB Output is correct
25 Correct 180 ms 99352 KB Output is correct
26 Correct 157 ms 99292 KB Output is correct
27 Correct 163 ms 99168 KB Output is correct
28 Correct 156 ms 99572 KB Output is correct
29 Correct 156 ms 99428 KB Output is correct
30 Correct 158 ms 99480 KB Output is correct
31 Correct 177 ms 99312 KB Output is correct
32 Correct 157 ms 99476 KB Output is correct