Maximum sum

#include <iostream>
#include <math.h>
int a[200000];

int main(){
	int n;
	std::cin >> n;

	for(int i = 0; i < n; i++){
		int in;
		std::cin >> in;
		a[i] = in;
	}
	if (a[0]< 0){
		a[0] = 0;
	}
	for(int i = 1; i < n; i++){
		a[i] = std::max(a[i-1]+a[i], 0);
	}
	int max = 0;
	for(int i = 0; i < n; i++){
		if (a[i] > max) max = a[i];
	}
	std::cout << max;
	return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: ACCEPTED

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: WRONG ANSWER

Test 14

Verdict: WRONG ANSWER

Test 15

Verdict: WRONG ANSWER