Submission #1016473

#	Time	Username	Problem	Language	Result	Execution time	Memory
1016473		_callmelucian	Matching (CEOI11_mat)	C++14	100 / 100	244 ms	41164 KiB

mat

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

typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pl;
typedef pair<int,int> pii;
typedef tuple<int,int,int> tt;

#define all(a) a.begin(), a.end()
#define filter(a) a.erase(unique(all(a)), a.end())

struct BIT {
    vector<int> tr;
    BIT (int sz) : tr(sz + 1, INT_MIN) {}

    int p (int k) { return k & -k; }

    void update (int k, int val) {
        for (; k < tr.size(); k += p(k))
            tr[k] = max(tr[k], val);
    }

    int query (int k, int ans = INT_MIN) {
        for (; k; k -= p(k)) ans = max(ans, tr[k]);
        return ans;
    }
};

const int mn = 2e6 + 6;
int p[mn], s[mn], lb[mn], rb[mn], z[mn];

bool ok (int i, int nxt) {
    // check if [i..nxt] is isomorphic to [0..p]
    // knowing that [i..nxt-1] is already isomorphic to [0..p-1]
    int p = nxt - i;
    if (lb[p] != -1) {
        int dist = p - lb[p];
        if (nxt - dist < 0 || s[nxt - dist] > s[nxt]) return 0; // s[nxt - dist] must be < s[nxt]
    }
    if (rb[p] != -1) {
        int dist = p - rb[p];
        if (nxt - dist < 0 || s[nxt - dist] < s[nxt]) return 0; // s[nxt - dist] must be > s[nxt]
    }
    return 1;
}

void zFunc (int n) {
    int x = 0, y = 0;
    for (int i = 1; i < n; i++) {
        z[i] = max(0, min(y - i + 1, z[i - x]));
        while (i + z[i] < n && ok(i, i + z[i]))
            x = i, z[i]++, y++;
    }
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);

    int n, m; cin >> n >> m;
    int len = n + m;

    for (int i = 1; i <= n; i++) {
        cin >> p[i];
        s[--p[i]] = i;
    }
    //s[n] = INT_MAX;
    for (int i = n; i < n + m; i++) cin >> s[i];

    BIT lt(n + 1), rt(n + 1);
    for (int i = 0; i < n; i++) {
        int lval = lt.query(s[i]), rval = rt.query(n - s[i] + 1);
        lb[i] = (lval == INT_MIN ? -1 : p[lval]);
        rb[i] = (rval == INT_MIN ? -1 : p[-rval]);
        lt.update(s[i], s[i]);
        rt.update(n - s[i] + 1, -s[i]);
    }
    zFunc(len);

    vector<int> ans;
    for (int i = n; i < len; i++)
        if (z[i] >= n) ans.push_back(i - n + 1);

    cout << ans.size() << "\n";
    for (int u : ans) cout << u << " ";

    return 0;
}

Compilation message (stderr)

mat.cpp: In member function 'void BIT::update(int, int)':
mat.cpp:20:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 |         for (; k < tr.size(); k += p(k))
      |                ~~^~~~~~~~~~~

• 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