题解 | 小苯的麦克斯

#include<bits/stdc++.h>
using namespace std;
using ll=long long;

int main(){
    ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
    ll T;
    cin>>T;
    while(T--){
        ll n;
        cin>>n;
        ll ans=-1e18;
        ll pre;
        cin>>pre;
        for(ll i=2;i<=n;i++){
            ll t;
            cin>>t;
            ll c=max(t,pre);
            ll j=0;
            while(true){
                if(j!=t&&j!=pre){
                    ans=max(ans,c-j);
                    break;
                }
                j++;
            }
            pre=t;
        }
        cout<<ans<<'\n';
    }

    return 0;
}