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

stack-queue/output/01-balanced-parentheses-trace.txt

@@ -0,0 +1,28 @@
+Balanced brackets: every step of four inputs
+============================================
+
+input: {[()]}   firstMismatch = -1
+  read '{' at 0: push '}'           waiting for (top first): }
+  read '[' at 1: push ']'           waiting for (top first): ] }
+  read '(' at 2: push ')'           waiting for (top first): ) ] }
+  read ')' at 3: pop ')', matches   waiting for (top first): ] }
+  read ']' at 4: pop ']', matches   waiting for (top first): }
+  read '}' at 5: pop '}', matches   waiting for (top first): (empty)
+  end of input: waiting for (empty) -> balanced
+
+input: ([)]   firstMismatch = 2
+  read '(' at 0: push ')'           waiting for (top first): )
+  read '[' at 1: push ']'           waiting for (top first): ] )
+  read ')' at 2: expected ']' -> NOT balanced
+
+input: ())   firstMismatch = 2
+  read '(' at 0: push ')'           waiting for (top first): )
+  read ')' at 1: pop ')', matches   waiting for (top first): (empty)
+  read ')' at 2: stack is empty, nothing to close -> NOT balanced
+
+input: (()   firstMismatch = 0
+  read '(' at 0: push ')'           waiting for (top first): )
+  read '(' at 1: push ')'           waiting for (top first): ) )
+  read ')' at 2: pop ')', matches   waiting for (top first): )
+  end of input: waiting for ) -> NOT balanced, openers left over
+