Arrays

Searching

Shrink the search space with ordered structure.

• Two sum II (sorted) (Medium)

Sliding window

Slide a contiguous window and maintain a running answer.

• Max subarray sum (size k) (Easy)
• Longest substring w/o repeat (Medium)

Sorting

Reorder a sequence and watch the invariants build.

• Bubble sort (Easy)
• Selection sort (Easy)
• Insertion sort (Easy)
• Merge sort (Medium)
• Quick sort (Medium)
• Heap sort (Medium)

Checkpoint

A graded check — pass to certify the Arrays topic.

Pattern Quest

Practice recognizing arrays problem shapes.

Arrays

Practice indexed-sequence techniques such as two pointers, in-place transforms, prefix state, and windows that replace repeated scans with deliberate linear passes.

• Find duplicate and missing (Medium)
• Find duplicate number (Medium)
• Find intersection of two sorted arrays (Easy)
• Find majority element (Easy)
• Jump game (Medium)
• Max product of subarray (Medium)
• Max profit selling stocks (Easy)
• Max rectangle in histogram (Hard)
• Max sum of subarray size K (Easy)
• Merge two sorted arrays (Easy)
• Move all zeros to end (Easy)
• Next permutation (Medium)
• Remove duplicates in place (Easy)
• Reverse array (Easy)
• Rotate array (Easy)
• Self exclude product (Medium)
• Task scheduler (Medium)
• Trap most water (Medium)
• Trap rain water (Hard)
• Two sum (Easy)