# GAME-OF-TWO-STACKS hackerrank Solution - Correct, Optimal and Working

``````/*
*  Author: Arpit Bhayani
*  https://arpitbhayani.me
*/
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <climits>
#include <deque>
#include <iostream>
#include <list>
#include <limits>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <vector>

#define ll long long

#define MIN(a, b) a < b ? a : b
#define MAX(a, b) a > b ? a : b

using namespace std;

int i = 0;
char ch;
while((ch = getchar()) != '\n') {
str[i++] = ch;
}
str[i] = '\0';
return i;
}

int arr1[100001];
int arr2[100001];

int foo(int n, int m, ll int x) {
ll int sum = 0;
int i = 0, j = 0;
int count = 0;

while (i < n) {
sum += (ll int) arr1[i];
i++;
if (sum > x) {
i--;
sum -= (ll int) arr1[i];
break;
}
}
count = i;

while (j < m) {
sum += (ll int) arr2[j];
j++;
while (sum > x && i > 0) {
i--;
sum -= (ll int) arr1[i];
}
count = (sum <= x) ? MAX( (count), (i + j) ) : count;
}

return count;
}

int main(int argc, char *argv[]) {
int t;
scanf("%d", &t);
while( t-- ) {
ll int x;
int n, m;
scanf("%d%d%lld", &n, &m, &x);

for (int i = 0 ; i < n; i++) {
scanf("%d", &arr1[i]);
}

for (int j = 0 ; j < m; j++) {
scanf("%d", &arr2[j]);
}

printf("%d\n", foo(n, m, x));
}
return 0;
}
``````