[LeetCode] [Easy] [JS] 155. Min Stack

 

1. 문제 및 예시

 

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.

 

 

 

2. 풀이

 

/**
 * initialize your data structure here.
 */
var MinStack = function() {
    this.st = [];
};

/** 
 * @param {number} x
 * @return {void}
 */
MinStack.prototype.push = function(x) {
    this.st.push(x);
};

/**
 * @return {void}
 */
MinStack.prototype.pop = function() {
    return this.st.pop();
};

/**
 * @return {number}
 */
MinStack.prototype.top = function() {
    return this.st[this.st.length-1];
};

/**
 * @return {number}
 */
MinStack.prototype.getMin = function() {
    return this.st.reduce((a, b)=> a > b ? b : a);
};

/** 
 * Your MinStack object will be instantiated and called as such:
 * var obj = new MinStack()
 * obj.push(x)
 * obj.pop()
 * var param_3 = obj.top()
 * var param_4 = obj.getMin()
 */

 

 

 

3. 결과

 

18 / 18 test cases passed.
Status: Accepted
Runtime: 140 ms
Memory Usage: 44.3 MB