What difficulties do you know in order of their increase?

In Go, complexity is usually considered in the context of algorithms and data structures. The complexity can be listed in ascending order:

• O(1) — constant complexity: execution time does not depend on input size.
• O(log n) — logarithmic complexity: for example, binary search.
• O(n) — linear complexity: iterating through all elements.
• O(n log n) — linear-logarithmic: for example, efficient sorting algorithms (quick sort).
• O(n²) — quadratic complexity: nested loops over the entire array.
• O(n³) — cubic complexity: triple nested loops.
• O(2^n) — exponential complexity: enumerating all subsets.
• O(n!) — factorial complexity: enumerating all permutations.

In Go, as in other languages, it is important to choose algorithms with minimal complexity to ensure performance.