Practice40 min
Practice: Matrix Choreography
In-place rotation, spiral walks, marker-based zeroing, and cycle-detecting digit sums.
Rotation and spiral drill the two boundary disciplines from the lesson; Set Matrix Zeroes rewards the first-row/first-column marker trick; Happy Number is cycle detection wearing an arithmetic costume.
Problems0 of 4 solved
- Not startedRotate Imagein-place layer rotation (or transpose + reverse rows)medium
- Not startedSpiral Matrixfour shrinking boundary pointersmedium
- Not startedSet Matrix Zeroesuse first row/column as zero markers (O(1) space)medium
- Not startedHappy Numbercycle detection (hash set or fast/slow pointers)easy