Submission #1144498

#	Time	Username	Problem	Language	Result	Execution time	Memory
1144498		kh0i	Matching (CEOI11_mat)	C++20	100 / 100	216 ms	35712 KiB

mat

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

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...)
#endif

using ll = long long;
using pii = pair<int, int>;

#define F first
#define S second
#define sz(x) (int)((x).size())
#define all(x) (x).begin(), (x).end()

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll get_rand(ll l, ll r) {
    assert(l <= r);
    return uniform_int_distribution<ll> (l, r)(rng);
}

const int N = 2e6 + 3;

int n, m, a[N];
int pos[N], pre[N], nxt[N];
int l[N], r[N];
int kmp[N];

void solve(){
    cin >> n >> m;
    for(int i = 1; i <= n; ++i)
        cin >> pos[i];
    for(int i = n + 1; i <= n + m; ++i){
        cin >> a[i];
        a[i] += n;
    }

    for(int i = 1; i <= n; ++i){
        a[pos[i]] = i;
        pre[i] = i - 1, nxt[i] = i + 1;
    }

    for(int i = n; i >= 1; --i){
        l[i] = r[i] = -1;
        int lv = pre[a[i]], rv = nxt[a[i]];
        nxt[lv] = rv;
        pre[rv] = lv;
        if(lv) l[i] = i - pos[lv];
        if(rv <= n) r[i] = i - pos[rv];
    }

    auto ok = [&](int i, int j){
        return i <= n and (l[i] == -1 or a[j - l[i]] < a[j]) and (r[i] == -1 or a[j - r[i]] > a[j]);
    };

    vector<int> res;
    for(int i = 2; i <= n + m; ++i){
        int j = kmp[i - 1];
        while(j and !ok(j + 1, i))
            j = kmp[j];
        kmp[i] = j + ok(j + 1, i);
        if(i >= 2 * n and kmp[i] == n)
            res.push_back(i - 2 * n + 1);
    }

    cout << sz(res) << "\n";
    for(int i = 0; i < sz(res); ++i)
        cout << res[i] << " \n"[i == sz(res) - 1];
}

int32_t main() {
    cin.tie(nullptr)->sync_with_stdio(0);
    #define task "troll"
    if(fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int test = 1;
//    cin >> test;
    for(int i = 1; i <= test; ++i){
//        cout << "Case #" << i << ": ";
        solve();
    }
    #ifdef LOCAL
        cerr << "\n[Time]: " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms.\n";
    #endif
    return 0;
}

Compilation message (stderr)

mat.cpp: In function 'int32_t main()':
mat.cpp:77:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
mat.cpp:78:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   78 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 9 / 9
• Subtask 5: 9 / 9
• Subtask 6: 9 / 9
• Subtask 7: 9 / 9
• Subtask 8: 9 / 9
• Subtask 9: 8 / 8
• Subtask 10: 10 / 10
• Subtask 11: 10 / 10