{leetcode}/problems/implement-queue-using-stacks/[LeetCode - Implement Queue using Stacks^]
Implement the following operations of a queue using stacks.
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push(x) — Push element x to the back of queue.
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pop() — Removes the element from in front of queue.
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peek() — Get the front element.
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empty() — Return whether the queue is empty.
Example:
MyQueue queue = new MyQueue(); queue.push(1); queue.push(2); queue.peek(); // returns 1 queue.pop(); // returns 1 queue.empty(); // returns false
Notes:
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You must use only standard operations of a stack — which means only
push to top,peek/pop from top,size, andis emptyoperations are valid. -
Depending on your language, stack may not be supported natively. You may simulate a stack by using a list or deque (double-ended queue), as long as you use only standard operations of a stack.
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You may assume that all operations are valid (for example, no pop or peek operations will be called on an empty queue).