Submission #1002030

#	Time	Username	Problem	Language	Result	Execution time	Memory
1002030		LilPluton	Watching (JOI13_watching)	C++14	100 / 100	656 ms	30256 KiB

watching

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization("unroll-loops")
/// author: LilPluton auuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu
#define OPT         ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define pb          push_back
#define arr         array
#define vll         vector<int>
#define int         long long
#define segment_tree int l=n*2,r=l+1,mid=(b+e)/2
#define fi          first
#define se          second
#define rep(i,j,k)  for(int i = j; i <= k; ++i)
#define all(a)      a.begin(),a.end()
#define pii         pair<int,int>
#define endll       '\n'
using namespace std;
const int N = 2e3 + 3;
const int INF = 1e18;
int a[N];

int dp[N][N];

int n, p, q;
int check(int w)
{
    for(int i = 0; i <= p; ++i)
    {
        int idx1 = 0, idx2 = 0;
        for(int j = 1; j <= n; ++j)
        {
            dp[i][j] = INF;
            while(idx1 < n && a[idx1 + 1] <= a[j] - w)
            {
                idx1++;
            }
            while(idx2 < n && a[idx2 + 1] <= a[j] - w * 2)
            {
                idx2++;
            }
            dp[i][j] = dp[i][idx2] + 1;
            if(i > 0)
            {
                dp[i][j] = min(dp[i][j], dp[i - 1][idx1]);
            }
        }

    }
    return dp[p][n];
}

signed main()
{
    
    cin >> n >> p >> q;
    for(int i = 1; i <= n; ++i)
        cin >> a[i];
    if(p + q >= n)
    {
        cout << 1;
        return 0;
    }
    sort(a + 1, a + n + 1);
    int lb = 1, rb = 1e9, ans, mid;
    while(lb <= rb)
    {
        mid = (lb + rb) >> 1;
        if(check(mid) > q)
        {
            lb = mid + 1;
            ans = mid;
        }
        else
        {
            rb = mid - 1;
        }
    }
    cout << lb;
    
} 

Compilation message (stderr)

watching.cpp:4: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    4 | #pragma GCC optimization("unroll-loops")
      | 
watching.cpp: In function 'int main()':
watching.cpp:65:27: warning: variable 'ans' set but not used [-Wunused-but-set-variable]
   65 |     int lb = 1, rb = 1e9, ans, mid;
      |                           ^~~

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