Submission #239234

#	Time	Username	Problem	Language	Result	Execution time	Memory
239234		aggu_01000101	Watching (JOI13_watching)	C++14	100 / 100	72 ms	7928 KiB

watching

#include <bits/stdc++.h>
#define int long long
#define INF 1000000000000000
#define lchild(i) (i*2 + 1)
#define rchild(i) (i*2 + 2)
#define mid(l, u) ((l+u)/2)
#define x(p) p.first
#define y(p) p.second
#define MOD 998244353
using namespace std;
int n, p, q;
vector<int> v;
int ct[2005][2];
int makect(int w){
    for(int i = 1;i<=n;i++){
        auto it = lower_bound(v.begin(), v.end(), v[i] + w);
        it--;
        int ind = it - v.begin();
        ct[i][0] = ind;
        it = lower_bound(v.begin(), v.end(), v[i] + w + w);
        it--;
        ind = it - v.begin();
        ct[i][1] = ind;
    }
}
bool f(int w){
    makect(w);
    int dp[p+1][q+1];
    dp[0][0] = 0;
    for(int i = 0;i<=p;i++){
        for(int j = 0;j<=q;j++){
            if(i==0 && j==0) continue;
            dp[i][j] = -INF;
            if(i>0){
                dp[i][j] = max(dp[i][j], ct[dp[i-1][j]+1][0]);
            }
            if(j>0){
                dp[i][j] = max(dp[i][j], ct[dp[i][j-1]+1][1]);
            }
            if(dp[i][j] == n) return true;
        }
    }
    return false;
}
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    cin>>n>>p>>q;
    int a[n];
    for(int i = 0;i<n;i++) cin>>a[i];
    sort(a, a+n);
    v.push_back(-1);
    for(int i = 0;i<n;i++) v.push_back(a[i]);
    p = min(p, n);
    q = min(q, n);
    int l = 1;
    int u = 1e9;
    int ans = 1e9;
    while(l<=u){
        int mid = mid(l, u);
        bool cando = f(mid);
        if(cando){
            ans = min(ans, mid);
            u = mid - 1;
        }
        else l = mid + 1;
    }
    cout<<ans<<"\n";
}

Compilation message (stderr)

watching.cpp: In function 'long long int makect(long long int)':
watching.cpp:25:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^

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