Submission #880008

#	Time	Username	Problem	Language	Result	Execution time	Memory
880008		cpptowin	Watching (JOI13_watching)	C++17	50 / 100	3 ms	15448 KiB

watching

#include<bits/stdc++.h>
#define fo(i,d,c) for(int i=d;i<=c;i++)
#define fod(i,c,d) for(int i=c;i>=d;i--)
#define maxn 1000010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout<<"\n";
#define int long long
#define inf (int)1e18
#define pii pair<int,int>
#define vii vector<pii>
#define lb(x) x&-x
#define bit(i,j) ((i>>j)&1)
#define offbit(i,j) (i^(1<<j))
#define onbit(i,j) (i|(1<<j))
#define vi vector<int>
template <typename T1, typename T2> bool minimize(T1 &a, T2 b){if (a > b) {a = b; return true;} return false;}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b){if (a < b) {a = b; return true;} return false;}
using namespace std;
int n,A,B;
int a[maxn];
int dp[N][N];
bool check(int val)
{
    fo(i,1,n) fo(j,0,B) dp[i][j] = inf;
    for(int i = 1,j = 1,k = 1; i <= n ; i++)
    {
        while(j < i and a[i] - a[j] >= val) j++;
        while(k < i and a[i] - a[k] >= 2 * val) k++;
        fo(x,0,B) dp[i][x] = dp[j - 1][x] + 1;
        fo(x,0,B - 1) dp[i][x + 1] = min(dp[i][x + 1],dp[k - 1][x]);
    }
    fo(i,0,B) if(dp[n][i] <= A) return 1;
    return 0;
}
main()
{
    #define name "TASK"
    if(fopen(name".inp","r"))
    {
       freopen(name".inp","r",stdin);
       freopen(name".out","w",stdout);
    }
    ios_base::sync_with_stdio(false);cin.tie(NULL);
    cin >> n >> A >> B;
    if(n <= A + B) return cout << 1,0;
    fo(i,1,n) cin >> a[i];
    sort(a + 1,a + n + 1);
    int l = 1,r = inf,ans;
    while(l <= r)
    {
        int mid = (l + r) >> 1;
        if(check(mid)) ans = mid,r = mid - 1;
        else l = mid + 1;
    }
    cout << ans;
}

Compilation message (stderr)

watching.cpp:38:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   38 | main()
      | ^~~~
watching.cpp: In function 'int main()':
watching.cpp:43:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |        freopen(name".inp","r",stdin);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
watching.cpp:44:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |        freopen(name".out","w",stdout);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 50 / 50
• Subtask 2: 0 / 50