题解 100% AC

#include <bits/stdc++.h>
using namespace std;
int a[100010];
int main(){
    int n;cin>>n;
    for(int i=1;i<=n;i++){
    	cin>>a[i];
    }
    sort(a+1,a+n+1);
    if((a[n]-a[1])%3==0){
    	cout<<a[n]-a[1];
        return 0;
    }
    int maxx[13]={-1,-1,-1},minn[13]={1001,1001,1001};
    for(int i=1;i<=n;i++){
    	int x=a[i]%3;
        if(a[i]>maxx[x]) maxx[x]=a[i];
        if(a[i]<minn[x]) minn[x]=a[i];
    }
    int ans=0;
    for(int i=0;i<=2;i++){
    	if(maxx[i]-minn[i]>ans) ans=maxx[i]-minn[i];
    }
    cout<<ans;
	return 0;
}