超时求调

#include<bits/stdc++.h>
using namespace std;
int main(){
	int l,n,m;
	cin>>l>>n>>m;
	int a[50005];
	for(int i=0;i<n;i++){cin>>a[i];}
	int lt=0,rt=n-1,mid,ans=1e9;
	while(m--){
		mid=(lt+rt)/2;
        while(lt<=rt){
            if(a[mid+1]-a[mid-1]<=ans){
			ans=a[mid+1]-a[mid-1];
			lt=mid;
		}
		else rt=mid;
        }
	}
	cout<<ans;
	return 0;
}