Input: pushed = [1,2,3,4,5], popped = [4,5,3,2,1] Output: true Explanation: We might do the following sequence: push(1), push(2), push(3), push(4), pop() -> 4, push(5), pop() -> 5, pop() -> 3, pop() -> 2, pop() -> 1
def validateStackSequences(self, pushed, popped): stack=[] idx=0 for elem in pushed: stack.append(elem) while stack and stack[-1]==popped[idx]: stack.pop() idx+=1 return len(stack)==0