(def valid (stack) (breakable:let q2 (- len.stack 1) (each q1 (range 0 (- len.stack 2)) (if (or (is stack.q1 stack.q2) (is (abs:- q1 q2) (abs:- stack.q1 stack.q2))) (break nil))) (break t)))
Thks for the "breakable" info
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