MEDIUM Backtracking
698. Partition to K Equal Sum Subsets
📖 Problem
Given an integer array nums and an integer k, return true if it is possible to divide the array into k non-empty subsets whose sums are all equal.
🧠 Visual Learning Aid
1 Model the input into the right structure
2 Choose the core technique and invariant
3 Execute step-by-step with a sample
4 Validate complexity and edge cases
JS/TS Refreshers
- •Array methods (`push`, `pop`, `shift`, `slice`)
- •Object/Map/Set usage patterns
- •Function parameter and return typing
- •Recursive function frames
- •Push/pop state undo
- •Pruning branches early
Logical Thinking Concepts
- •Define invariants before coding
- •Check edge cases first (`[]`, single element, duplicates)
- •Estimate time/space before implementation
- •Apply Backtracking reasoning pattern
- •Apply Recursion reasoning pattern
💡 Approach
- → Calculate total sum of array
- → Target sum for each subset must be total/k
- → Use backtracking to try partitioning
- → Track used elements and current subset sum
- → Time: O(n^(k-1)), Space: O(k) for recursion
🧭 Prerequisites
🛠️ Hints & Pitfalls
Hints
- •Calculate total sum of array
- •Target sum for each subset must be total/k
- •Use backtracking to try partitioning
Common Pitfalls
- •Track used elements and current subset sum
- •Time: O(n^(k-1)), Space: O(k) for recursion
🧪 Test Cases
Hidden tests on submit: 1
Test Case 1
Not run Input:
canPartitionKSubsets([4,3,2,3,5,2,1], 4); Expected:
true Test Case 2
Not run Input:
canPartitionKSubsets([1,2,3,4], 3); Expected:
false Test Case 3
Not run Input:
canPartitionKSubsets([1,1,1,1,1,1], 5); Expected:
false 📝 Code Editor
📤 Output