RT 60pts代码（很简单的O(n)）

#include <bits/stdc++.h>
using namespace std;
int n,a[1000001],l,minn=0x3f3f3f;
int main(){
	int n;
	cin>>n;
	for(int i=1;i<=n;i++) cin>>a[i];
	sort(a+1,a+n+1);
	for(int i=1;i<=n+1;i++){
		if(i==1||a[i]==a[i-1]+1&&i!=n+1) l++;
		else{
			minn=min(minn,l);
			l=1;
		}
	}
	cout<<minn<<endl;
}