Submission #1005409

#	Time	Username	Problem	Language	Result	Execution time	Memory
1005409		rahidilbayramli	Watching (JOI13_watching)	C++17	100 / 100	264 ms	31064 KiB

watching

#pragma GCC optimize("-O3")
#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define vl vector<ll>
#define vi vector<int>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define pb push_back
#define p_b pop_back
#define f first
#define s second
using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
const ll sz = 2e3+5;
ll a[sz], dp[sz][sz], n, p, q;
ll lst(ll pos, ll mid)
{
    ll g = a[pos + 1] + mid - 1;
    ll l = pos + 1, r = n - 1, res = pos;
    while(l <= r)
    {
        ll mid = (l + r) / 2;
        if(a[mid] <= g)
        {
            res = max(res, mid);
            l = mid + 1;
        }
        else
            r = mid - 1;
    }
    return res;
}
bool ch(ll mid)
{
    dp[0][0] = -1;
    for(ll i = 0; i <= p; i++)
    {
        for(ll j = 0; j <= q; j++)
        {
            if(i == 0 && j == 0)
                continue;
            if(i == 0)
                dp[i][j] = lst(dp[i][j-1], mid * 2);
            else    if(j == 0)
                dp[i][j] = lst(dp[i-1][j], mid);
            else
                dp[i][j] = max(lst(dp[i-1][j], mid), lst(dp[i][j-1], mid * 2));
            if(dp[i][j] == n - 1)
                return true;
        }
    }
    return false;
}
void solve()
{
    ll i, j;
    cin >> n >> p >> q;
    for(i = 0; i < n; i++)
        cin >> a[i];
    sort(a, a+n);
    if(p + q >= n)
    {
        cout << "1\n";
        return;
    }
    ll l = 1, r = a[n-1], ans;
    while(l <= r)
    {
        ll mid = (l + r) / 2;
        if(ch(mid))
        {
            ans = mid;
            r = mid - 1;
        }
        else
            l = mid + 1;
    }
    cout << ans << "\n";
}
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    ll tests = 1;
    //cin >> tests;
    while(tests--)
    {
        solve();
    }
}

Compilation message (stderr)

watching.cpp: In function 'void solve()':
watching.cpp:63:11: warning: unused variable 'j' [-Wunused-variable]
   63 |     ll i, j;
      |           ^

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