Submission #60054918

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Source Code Expand

#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <map>
#include <set>
#include <atcoder/all>
using namespace std;

#define REP(i, n) for (int i = 0; i < n; i++)
#define FOR(i, l, r) for (int i = l; i <= r; i++)
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)

using ll = long long;
using VI = vector<int>;
using VL = vector<ll>;
using VVI = vector<VI>;
using VVL = vector<VL>;

int calc(VI a) {
    int n = a.size();
    // cout << n << endl;
    // REP(i,n) cout << a[i] << " ";
    // cout << endl;
    int ans = 0;
    map<int, int> cnt;
    int r = 0;
    REP(l,n) {
        if (r < l) r = l;
        while (r < n && a[r] != -1 && cnt[a[r]] == 0) {
            cnt[a[r]]++;
            r++;
        }
        // cout << l << " " << r << endl;
        chmax(ans, r - l);
        if (a[l] != -1) {
            cnt[a[l]]--;
        }
    }
    return ans;
}

int main()
{
    int n;
    cin >> n;
    VI a(n);
    REP(i,n) cin >> a[i];

    int ans = 0;
    VI b, c;
    REP(i,n/2) {
        int j1 = 2 * i;
        int j2 = 2 * i + 1;
        if (a[j1] == a[j2]) {
            b.push_back(a[j1]);
        } else {
            b.push_back(-1);
        }
        j1++;
        j2++;
        if (j2 >= n) continue;
        if (a[j1] == a[j2]) {
            c.push_back(a[j1]);
        } else {
            c.push_back(-1);
        }
    }

    ans = max(calc(b), calc(c));
    cout << 2 * ans << endl;
}

Submission Info

Judge Result