Submission #252218

#	Time	Username	Problem	Language	Result	Execution time	Memory
252218		IgorI	Watching (JOI13_watching)	C++17	100 / 100	254 ms	4376 KiB

watching

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<vector<int> > vvi;
typedef vector<ll> vll;

#define forn(i, n) for (int (i) = 0; (i) != (n); (i)++)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define popcount(x) __builtin_popcount(x)
#define popcountll(x) __builtin_popcountll(x)
#define fi first
#define se second
#define re return
#define pb push_back
#define uniq(x) sort(all(x)); (x).resize(unique(all(x)) - (x).begin())

#ifdef LOCAL
#define dbg(x) cerr << __LINE__ << " " << #x << " " << x << endl
#define ln cerr << __LINE__ << endl
#else
#define dbg(x) void(0)
#define ln void(0)
#endif // LOCAL

int cx[4] = {-1, 0, 1, 0};
int cy[4] = {0, -1, 0, 1};
string Yes[2] = {"No", "Yes"};
string YES[2] = {"NO", "YES"};

const int N = 3400;

int n, p, q;
int a[N];
int small[N], big[N];

int can(int M)
{
    int j = 0;
    for (int i = 0; i < n; i++)
    {
        while (j < n && a[j] - a[i] + 1 <= M) j++;
        small[i] = j;
    }
    small[n] = n;
    j = 0;
    for (int i = 0; i < n; i++)
    {
        while (j < n && a[j] - a[i] + 1 <= 2 * M) j++;
        big[i] = j;
    }
    big[n] = n;
    vector<vector<int> > dp(p + 1, vector<int>(q + 1));
    for (int s = 0; s <= p; s++)
    {
        for (int b = 0; b <= q; b++)
        {
            if (s < p)
            {
                dp[s + 1][b] = max(dp[s + 1][b], small[dp[s][b]]);
            }
            if (b < q)
            {
                dp[s][b + 1] = max(dp[s][b + 1], big[dp[s][b]]);
            }
        }
    }
    return (dp[p][q] == n);
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> p >> q;
    for (int i = 0; i < n; i++)
    {
        cin >> a[i];
    }
    if (p + q >= n)
    {
        cout << 1;
        return 0;
    }
    sort(a, a + n);
    int L = 0, R = 1e9 + 7;
    while (L + 1 < R)
    {
        int M = (L + R) / 2;
        if (can(M)) R = M;
        else L = M;
    }
    cout << R << "\n";
}

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50