3308 - Matching(WithoutSegTree).cpp

#define _CRT_SECURE_NO_WARNINGS 1
#define _CRT_DECLARE_NONSTDC_NAMES 0 // for using y1 as variable name

#include <algorithm>
#include <cstdio>
#include <iostream>
#include <string>
#include <utility>
#include <vector>
using namespace std;

using ll = long long int;

int n, m;
vector<int> a, b;

vector<int> fail;
vector<int> smaller, bigger;

bool isSame(int posa, int posb, const vector<int>& b)
{
    if (smaller[posa] != -1 && b[posb - posa + smaller[posa]] >= b[posb]) return false;
    if (bigger[posa] != -1 && b[posb - posa + bigger[posa]] <= b[posb]) return false;
    return true;
}

void init_fail()
{
    fail.clear();
    fail.resize(n, 0);

    vector<int> nxt(n), pre(n), pos(n, n);
    for (int i = 0; i < n; ++i) {
        nxt[i] = i + 1;
        pre[i] = i - 1;
    }
    for (int i = 0; i < n; ++i) {
        pos[a[i]] = min(pos[a[i]], i);
    }
    bigger.resize(n);
    smaller.resize(n);
    for (int i = n - 1; i >= 0; --i) {
        int v = a[i];
        if (nxt[v] == n) bigger[i] = -1;
        else bigger[i] = pos[nxt[v]];
        if (pre[v] == -1) smaller[i] = -1;
        else smaller[i] = pos[pre[v]];

        if (pre[v] != -1) nxt[pre[v]] = nxt[v];
        if (nxt[v] != n) pre[nxt[v]] = pre[v];
    }

    int j = 0;
    for (int i = 1; i < n; ++i) {
        while (j > 0 && isSame(j, i, a) == false) {
            j = fail[j - 1];
        }
        if (isSame(j, i, a) == true) {
            fail[i] = j + 1;
            j++;
        }
    }
}

void get(vector<int>& res)
{
    init_fail();
    res.clear();

    int j = 0;
    for (int i = 0; i < m; ++i) {
        while (j > 0 && isSame(j, i, b) == false) {
            j = fail[j - 1];
        }
        if (isSame(j, i, b) == true) {
            j++;
        }
        if (j == n) {
            res.push_back(i - n + 1);
            j = fail[j - 1];
        }
    }
}

int main(void)
{
#ifdef CUBE_PS
    freopen("input.txt", "r", stdin);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n >> m;
    a.resize(n);
    b.resize(m);
    for (int i = 0; i < n; ++i) {
        int v;
        cin >> v;
        a[v - 1] = i;
    }
    for (int i = 0; i < m; ++i) {
        cin >> b[i];
    }

    vector<int> res;
    get(res);

    cout << res.size() << "\n";
    for (int v : res) cout << v + 1 << " ";

    return 0;
}