Add stack-queue module: ten stack and queue interview problems, monotonic stack, min stack, queue from stacks and stack from a queue, brute-force cross-checks, dry-run traces, operation counts, pitfalls (11 tests)

Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b6nxynun5JFivebVb1
2026-11-12 22:35:43 +05:30
parent c5c435ae20
commit b9aeb78b24
36 changed files with 2164 additions and 0 deletions
@@ -0,0 +1,16 @@
+Queue from two stacks, and stack from one queue
+===============================================
+
+QueueViaStacks (stacks shown top first)
+  enqueue(1)    in=[1]  out=[]
+  enqueue(2)    in=[2, 1]  out=[]
+  enqueue(3)    in=[3, 2, 1]  out=[]
+  dequeue() = 1  in=[]  out=[2, 3]   transfers so far: 3
+  enqueue(4)    in=[4]  out=[2, 3]
+  dequeue() x3 = 2, 3, 4  in=[]  out=[]   transfers so far: 4
+
+StackViaQueue
+  push(1)       queue(front=top)=[1]   rotations so far: 0
+  push(2)       queue(front=top)=[2, 1]   rotations so far: 1
+  push(3)       queue(front=top)=[3, 2, 1]   rotations so far: 3
+  pop() x2 = 3, 2   queue(front=top)=[1]