1020. Partition Array Into Three Parts With Equal Sum

Given an array `A` of integers, return `true` if and only if we can partition the array into three non-empty parts with equal sums.

Formally, we can partition the array if we can find indexes `i+1 < j` with `(A[0] + A[1] + ... + A[i] == A[i+1] + A[i+2] + ... + A[j-1] == A[j] + A[j-1] + ... + A[A.length - 1])`

Example 1:

Input:

```[0,2,1,-6,6,-7,9,1,2,0,1]
```

Output:

```true
Explanation: 0 + 2 + 1 = -6 + 6 - 7 + 9 + 1 = 2 + 0 + 1
```

Example 2:

Input:

```[0,2,1,-6,6,7,9,-1,2,0,1]
```

Output:

```false
```

Example 3:

Input:

```[3,3,6,5,-2,2,5,1,-9,4]
```

Output:

```true
Explanation: 3 + 3 = 6 = 5 - 2 + 2 + 5 + 1 - 9 + 4
```

Note:

1. `3 <= A.length <= 50000`
2. `-10000 <= A[i] <= 10000`
```class Solution {

/**
* @param Integer[] \$A
* @return Boolean
*/
function canThreePartsEqualSum(\$A) {
\$mean = array_sum(\$A) / 3;
if (floor(\$mean) != \$mean){
return false;
}

\$count  = 0;
\$sum = 0;
\$i = 0;
while (\$i < count(\$A)){
\$sum += \$A[\$i];
\$i ++;
if(\$sum == \$mean){
\$count ++;
\$sum = 0;
}
}
return \$count == 3;
}
}```