LeetCode/InterviewGolden/cpp/ig_0305.cpp at master · duycc/LeetCode · GitHub

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/**
 * @file     ig_0305.cpp
 * @brief    https://leetcode-cn.com/problems/sort-of-stacks-lcci/
 * @author   YongDu
 * @date     2021-09-10
 */
class SortedStack {
public:
  SortedStack() {}

  void push(int val) {
    if (stk1st.empty()) {
      stk1st.push(val);
    } else {
      while (!stk1st.empty() && stk1st.top() < val) {
        stk2nd.push(stk1st.top());
        stk1st.pop();
      }
      stk1st.push(val);
      while (!stk2nd.empty()) {
        stk1st.push(stk2nd.top());
        stk2nd.pop();
      }
    }
  }

  void pop() {
    if (stk1st.empty())
      return;
    stk1st.pop();
  }

  int peek() {
    if (stk1st.empty())
      return -1;
    return stk1st.top();
  }

  bool isEmpty() { return stk1st.empty(); }

private:
  stack<int> stk1st;
  stack<int> stk2nd;
};