DSA Complexity means how much time and space (memory) a Data Structure or Algorithm (DSA) needs to solve a problem.
You're solving a puzzle.
Time Complexity = How long it takes you to solve it.
Space Complexity = How much table space (memory) you need while solving it.
Time Complexity
How fast an algorithm runs as the input gets bigger.
Example:
If you check each number in a list of 10 elements, it takes 10 steps.
For 100 elements, it takes 100 steps.
This is called O(n) ā "linear time".
Space Complexity
How much extra memory the algorithm uses while running.
Example:
Complexity Meaning Example
O(1) Constant time Accessing one item from an array
O(log n) Logarithmic Binary search
O(n) Linear time Loop through an array
O(n²) Quadratic Nested loops (e.g., bubble sort)