NOTE
Divide and Conquer
Split a problem into smaller independent subproblems, solve them, then combine their results.
This is a historical learning note and may contain outdated or incomplete understanding.
Divide-and-conquer algorithms split a problem into smaller subproblems of the same form, solve them recursively, and combine the results.
Merge sort and many tree/geometry algorithms follow this structure. Complexity is often analyzed with a recurrence such as T(n)=aT(n/b)+f(n).
It works best when subproblems are largely independent; heavy overlap is a signal that dynamic programming/memoization may be more appropriate.