Partitioning & Window LeetCode 75

Sort Colors / visualized

Sort an array of 0s, 1s, and 2s in one pass, in place — Dijkstra's Dutch National Flag partition. Three regions grow as mid scans: 0s to the left, 2s to the right, everything unclassified in the middle.

Array of 0 / 1 / 2 (comma-separated)

Execution

idle

[0, low) → 0s [low, mid) → 1s [mid, high] → unknown (high, end] → 2s

Press Run to begin.

0 / 0

Speed

Java · running line

0 (red) 1 (white) 2 (blue)

O(n) time · O(1) space · mid only advances after a 0 or 1 swap — after swapping in a 2, the new value at mid is unexamined, so it stays put.