Merge branch 'master' of git.hxr.so:yige/js-practice

README.md

@@ -286,9 +286,15 @@ LeetCode 与 LintCode 解题记录。此为个人练习仓库，代码中对重
 ## 栈
 
 - [最大矩阵](src/stack/maximal-rectangle.js)
+
   - LeetCode 85. 最大矩阵 <https://leetcode-cn.com/problems/maximal-rectangle/>
   - LintCode 510. 最大矩阵 <https://www.lintcode.com/problem/maximal-rectangle/description>
 
+- [最小栈](src/stack/min-stack.js)
+
+  - LeetCode 155. 最小栈 <https://leetcode-cn.com/problems/min-stack/>
+  - LintCode 12. 带最小值操作的栈 <https://www.lintcode.com/problem/min-stack/description>
+
 ## 数学
 
 - [阶乘后的零](src/math/factorial-trailing-zeroes.js)

src/stack/min-stack.js

@@ -0,0 +1,47 @@
+/**
+ * initialize your data structure here.
+ */
+export const MinStack = function () {
+  this.stack = []
+  this.minStack = [Infinity]
+}
+
+/**
+ * @param {number} x
+ * @return {void}
+ */
+MinStack.prototype.push = function (x) {
+  this.stack.push(x)
+  this.minStack.push(Math.min(this.minStack[this.minStack.length - 1], x))
+}
+
+/**
+ * @return {void}
+ */
+MinStack.prototype.pop = function () {
+  this.stack.pop()
+  this.minStack.pop()
+}
+
+/**
+ * @return {number}
+ */
+MinStack.prototype.top = function () {
+  return this.stack[this.stack.length - 1]
+}
+
+/**
+ * @return {number}
+ */
+MinStack.prototype.getMin = function () {
+  return this.minStack[this.minStack.length - 1]
+}
+
+/**
+ * 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()
+ */

test/stack/min-stack.test.js

@@ -0,0 +1,13 @@
+import { MinStack } from '../../src/stack/min-stack'
+
+test('最小栈', () => {
+  var obj = new MinStack()
+  obj.push(1)
+  obj.push(3)
+  obj.push(2)
+  obj.pop()
+  var top = obj.top()
+  var min = obj.getMin()
+  expect(top).toBe(3)
+  expect(min).toBe(1)
+})