Hello all,

I made the below solution for this question. It also passed all test cases given in the editorial.

But, Codechef is throwing WA when submitted. What could be the reason?

#include<iostream>
#include<vector>

typedef long long int ll;

using namespace std;

// RECURSIVE CODE
ll total(ll N, ll *A, ll *B, ll X, ll Y)
{
	if(N==0)
		return 0;

	return max(X>0?(A[N-1]+total(N-1, A, B, X-1, Y)):0, Y>0?(B[N-1]+total(N-1, A, B, X, Y-1)):0);
}

// MEMOIZED CODE
ll mem_total(ll N, ll *A, ll *B, ll X, ll Y, ll **mem)
{
	if(N==0)
		return 0;

	if((X>0 && mem[X-1][Y] != 0) && (Y>0 && mem[X][Y-1] != 0))
		mem[X][Y] = max(A[N-1] + mem[X-1][Y], B[N-1] + mem[X][Y-1]);
	else
		mem[X][Y] = max(X>0?(A[N-1]+mem_total(N-1, A, B, X-1, Y, mem)):0,
					Y>0?(B[N-1]+mem_total(N-1, A, B, X, Y-1, mem)):0);
}

main()
{
	ll N, X, Y;

	cin>>N>>X>>Y;
	
	ll **mem;

	mem = new ll*[X+1];
	for(int i=0; i<=X; i++)
		mem[i] = new ll[Y+1];

	ll A[N], B[N];

	for(ll i=0; i<N; i++)
		cin>>A[i];
	for(ll i=0; i<N; i++)
		cin>>B[i];

	mem_total(N, A, B, X, Y, mem);

	cout<<mem[X][Y]<<endl;
}