minStack-007 (feature): implement minStack

Author: Diego Flores Castillo

LeetcodeProblems/Algorithms/Min_Stack.js

@@ -19,51 +19,45 @@ minStack.pop();
 minStack.top();      --> Returns 0.
 minStack.getMin();   --> Returns -2.
 */
-
 class MinStack {
   constructor() {
-    this.minStack = [];
     this.stack = [];
-    this.countStack = 0;
-    this.countMinStack = 0;
   }
 
   push(value) {
-    if (this.countStack === this.stack.length) this.stack.push(value);
-    else this.stack[this.countStack] = value;
-    this.countStack++;
+    const length = this.stack.length;
+    this.stack[length] = value;
+  }
+
+  getStack() {
+    return this.stack;
+  }
 
-    const min = this.getMin();
-    if (min === null || min >= value) {
-      if (this.countMinStack === this.minStack.length)
-        this.minStack.push(value);
-      else this.minStack[this.countMinStack] = value;
-      this.countMinStack++;
+  getMin() {
+    let min = this.stack[0];
+    for (let value of this.stack) {
+      min = min > value ? value : min;
     }
+    return min;
   }
 
   pop() {
-    if (this.countStack === 0) return null;
-
-    var elem = this.stack[this.countStack - 1];
-    this.countStack--;
-
-    if (elem === this.minStack[this.countMinStack - 1]) this.countMinStack--;
-
-    return elem;
+    const newStack = [];
+    const length = this.stack.length;
+    const number = this.stack[length - 1];
+    for (let i = 0; i < length - 1; i++) {
+      newStack[i] = this.stack[i];
+    }
+    this.stack = newStack;
+    return number;
   }
 
   top() {
-    if (this.countStack === 0) return null;
-
-    return this.stack[this.countStack - 1];
+    const length = this.stack.length;
+    const number = this.stack[length - 1];
+    return number;
   }
 
-  getMin() {
-    if (this.countMinStack === 0) return null;
-
-    return this.minStack[this.countMinStack - 1];
-  }
 }
 
 module.exports.MinStack = MinStack;

LeetcodeProblemsTests/Algorithms/Min_Stack_Test.js

@@ -1,5 +1,5 @@
-const assert = require('assert');
-const MinStack = require('../../LeetcodeProblems/Algorithms/Min_Stack').MinStack;
+const assert = require("assert");
+const MinStack = require("../../LeetcodeProblems/Algorithms/Min_Stack").MinStack;
 
 function test() {
   var minStack = new MinStack();
@@ -8,6 +8,8 @@ function test() {
   minStack.push(-3);
   assert.equal(minStack.getMin(), -3);
   assert.equal(minStack.pop(), -3);
+  console.log(minStack.getStack());
+
   assert.equal(minStack.top(), 0);
   assert.equal(minStack.getMin(), -2);
 }