Language: C++

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define l long
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define fi first
#define se second
#define M1 1000000007
#define M2 998244353
#define ww while
#define fl(i,a,b)  for(ll i=a;i<b;i++)
#define bfl(i,a,b) for(ll i=b-1;i>=a;i--)
#define f(i,n)     for(ll i=0;i<n;i++)
#define bf(i,n)    for(ll i=n-1;i>=0;i--)


#define p0(a) cout << a << " "
#define p1(a) cout << a << endl
#define p2(a, b) cout << a << " " << b << endl
#define p3(a, b, c) cout << a << " " << b << " " << c << endl
#define p4(a, b, c, d) cout << a << " " << b << " " << c << " " << d << endl

#define bn "\n"

//------------------------------------------------------------------------ 
// #define V(a) vector<a>
// #define vt() vector< tuple < ll ,ll ,ll > > ;
// #define vector< ll ,ll > pv;
// vector< pair <ll,ll> > vect;


//------------------------------------------------------------------------

ll modI(ll a,ll m);
ll gcd(ll a,ll b);
ll powM(ll x,ll y,ll m);
ll swap(ll a,ll b);

void swap(ll& a,ll& b)
{
    ll tp=a;
    a=b;
    b=tp;
}

ll gcd(ll x,ll y)
{
    if(x==0) return y;
    return gcd(y%x,x);
}

ll powM(ll x,ll y,ll m)
{
    ll ans=1,r=1;
    x%=m;
    ww(r>0&&r<=y)
    {
        if(r&y)
        {
            ans*=x;
            ans%=m;
        }
        r<<=1;
        x*=x;
        x%=m;
    }
    return ans;
}
 
ll modI(ll a, ll m)
{
    ll m0=m,y=0,x=1;
    if(m==1) return 0;
    ww(a>1)
    {
        ll q=a/m;
        ll t=m;
        m=a%m;
        a=t;
        t=y;
        y=x-q*y;
        x=t;
    }
    if(x<0) x+=m0;
    return x;
}

//---------------------------------------------------------------------------

// variable = Expression1 ? Expression2 : Expression3
// max = (n1 > n2) ? n1 : n2; 
// (n>m) ? cout<<"True"<<endl:cout<<"false"<<endl ;

// ---------------------------------------------------------------------------	

// ll n;cin>>n;ll a[n];for(ll i=0;i<n;i++)cin>>a[i];    
// for(ll i=0;i<n;i++)cout<<a[i];
// ll a,b;cin>>a>>b;   

//----------------------------------------------------------------------------

// vector< tuple < ll ,ll ,ll > > tv;
// vector< ll ,ll > pv;


//----------------------------------------------------------------------------


ll main() {
	
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(0);
	ll tt=1;
   // cin>>tt;
	ww(tt--)
	{
	       ll n,m; ll k; cin>>n>>m>>k;
    	vector<ll>v1(n+1);
    	vector<ll>v2(n+1);
    	 v1[0] = v2[0] = 0;
    	fl(i,1,n+1){ cin>>v1[i]; v1[i] =v1[i]+ v1[i-1]; }
    	fl(i,1,m+1){ cin>>v2[i]; v2[i] =v2[i]+ v2[i-1]; }
    	ll cnt = 0;
    	ll index1 = n, index2 = 0;
    	ww(index1>=0 && index2<=m)
    	{
    		ww(index1>=0 && v1[index1]+v2[index2]>k) index1--;
    		ww(index2<=m && v1[index1]+v2[index2]<=k) index2++;
    		index2--;
    		cnt = max( cnt , index1 + index2 );
    		index2++;
    	}
    	index1 = 0, index2 = m;
    	ww(index1<=n && index2>=0)
    	{
    		ww(index2>=0 && v1[index1]+v2[index2]>k) index2--;
    		ww(index1<=n && v1[index1]+v2[index2]<=k) index1++;
    		index1--;
    		cnt = max( cnt , index1 + index2 );
    		index1++;
    	}
    //	cout<<cnt;
    p1(cnt);
	   
    	 
	   
	   
	    
	}
	
	return 0;
}


Compiler output:
cc1plus: error: '::main' must return 'int'