C :

#include<stdio.h>
int main()
{
	int max,s,a[101],t,n,i;
	scanf("%d",&t);
	while(t--)
	{
		scanf("%d",&n);
		for(i=0;i<n;i++)
			scanf("%d",&a[i]);
		s=0;
		max=0;
		for(i=0;i<n;i++)
		{
			if(a[i]==1)
				s++;
			else
			{
				if(s>max)
					max=s;
				s=0;
			}				
		}
		if(a[n-1]==1&&s>max)
			max=s;
		printf("%d\n",max);
	}
}

C++ :

//{{{-------------------head file-------------------//
//#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <set>
#include <map>
#include <list>
#include <cmath>
#include <stack>
#include <queue>
#include <string>
#include <vector>
#include <bitset>
#include <cstdio>
#include <cassert>
#include <climits>
#include <cstring>
#include <numeric>
#include <iostream>
#include <algorithm>
#define  pb push_back
#define  mp make_pair
#define  inst insert
#define  se second
#define  fi first
#define  sz(x) ((int)(x).size())
#define  ForEach(i,c) for(__typeof((c).begin()) i = (c).begin();i != (c).end();i++)
using namespace std;

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
//}}}------------------end line--------------------//


int main() {
	int T, n;
	cin >> T;
	while(T--) {
		cin >> n;
		vector<int> v(n);
		for(int i = 0; i < n; i++)
			cin >> v[i];
		int len = v[0], ans = v[0];
		for(int i = 1; i < n; i++) {
			if(v[i] == 1) {
				len++;
				ans = max(ans, len);
			} else {
				len = 0;	
			}
		}
		cout << ans << endl;
	}
    return 0;
}