题解

#include<bits/stdc++.h>
using namespace std;
int n,a[100001],longest=1,maxn;
int main(){
    cin>>n;
    for(int i=1;i<=n;i++)cin>>a[i];
    for(int i=2;i<=n;i++){
        if(a[i]-1==a[i-1])longest++;
        else {maxn=max(maxn,longest);longest=1;}
    }
    maxn=max(maxn,longest);
    cout<<maxn;
    return 0;
}