题解

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;

int main(){
    int s=1;
    int a[100010];
    vector<int>maxs;
    int n;
    cin >> n;
    if (n==0 || n==1){cout<<n;return 0;}
    for (int i=1;i<=n;i++) cin >> a[i];
    for (int i=2;i<=n;i++){
        if (a[i-1]+1==a[i]) s++;
        else s=1;
        maxs.push_back(s);
    }
    sort(maxs.begin(),maxs.end(),greater<>());
    cout << maxs[0];
    return 0;
}