Easy answer in 1 loop
Complexity
Time complexity: O(n)

Space complexity: O(1)
Code

<!-- Describe your approach to solving the problem. -->

# Complexity
- Time complexity: ***O(n)***
<!-- Add your time complexity here, e.g. $$O(n)$$ -->

- Space complexity: ***O(1)***
<!-- Add your space complexity here, e.g. $$O(n)$$ -->

# Code
```java []
class Solution {
    public boolean isBalanced(String num) {
        int leftSum = 0;
        int rightSum = 0;
        
        for(int i=0; i<num.length(); i++){
            if(i%2 == 0){
                leftSum += num.charAt(i) - '0'; 
            }
            else{
                rightSum += num.charAt(i) - '0'; 
            }
        }
        return leftSum == rightSum;
    }
}
```
['Java']