MinStack-leetcode155

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.

• push(x) -- Push element x onto stack.
• pop() -- Removes the element on top of the stack.
• top() -- Get the top element.
• getMin() -- Retrieve the minimum element in the stack.

Example:

MinStack minStack = new MinStack();
minStack.push(-2);
minStack.push(0);
minStack.push(-3);
minStack.getMin();   --> Returns -3.
minStack.pop();
minStack.top();      --> Returns 0.
minStack.getMin();   --> Returns -2.

 

這裏原本覺得用上stack類，能夠垂手可得的實現，固然我還能夠使用其餘的隊列實現。只是getMin要特殊處理一下，畢竟statck就只有那幾個方法，會比較麻煩一點，可是看到別的大神是那麼寫的，智商抓急，這樣寫的確比較方便,就是若是想看size會比較奇怪！