Short variable declaration in Go - Time & Space Complexity

Time Complexity: Short variable declaration

O(n)

Understanding Time Complexity

Let's see how the time cost changes when using short variable declarations in Go.

We want to know if this way of declaring variables affects how long the program takes to run.

Scenario Under Consideration

Analyze the time complexity of the following code snippet.

func sumSlice(nums []int) int {
  sum := 0
  for _, num := range nums {
    sum += num
  }
  return sum
}
    

This code sums all numbers in a list using short variable declaration for sum and num.

Identify Repeating Operations

Identify the loops, recursion, array traversals that repeat.

• Primary operation: Looping through each number in the list.
• How many times: Once for every number in the list.

How Execution Grows With Input

As the list gets bigger, the program does more additions, one for each number.

Input Size (n)	Approx. Operations
10	10 additions
100	100 additions
1000	1000 additions

Pattern observation: The work grows directly with the number of items.

Final Time Complexity

Time Complexity: O(n)

This means the time to finish grows in a straight line as the list gets longer.

Common Mistake

[X] Wrong: "Using short variable declaration makes the loop faster."

[OK] Correct: The way variables are declared does not change how many times the loop runs or how many additions happen.

Interview Connect

Understanding how loops and variable declarations affect time helps you explain your code clearly and shows you know what really matters for speed.

Self-Check

"What if we replaced the loop with recursion? How would the time complexity change?"