1st solution for Min Max Stack Construction

Author: wellingtonleitedev

src/min-max-stack-construction/min-max-stack-construction.js

@@ -0,0 +1,102 @@
+// Feel free to add new properties and methods to the class.
+class MinMaxStack {
+  constructor() {
+    this.stack = [];
+    this.minValue = null;
+    this.maxValue = null;
+  }
+
+  getStack() {
+    return this.stack;
+  }
+
+  peek() {
+    return this.stack[this.stack.length - 1];
+  }
+
+  pop() {
+    this.minValue = null;
+    this.maxValue = null;
+
+    const length = this.stack.length - 1;
+    const poped = this.stack[length];
+    let oldStack = this.stack;
+    let start = 0;
+    let end = length - 1;
+
+    this.stack = [];
+
+    if (start === end) {
+      this.push(oldStack[start]);
+    }
+
+    while (start < end) {
+      this.push(oldStack[start]);
+      this.push(oldStack[end]);
+
+      start += 1;
+      end -= 1;
+    }
+
+    return poped;
+  }
+
+  push(number) {
+    this.minValue = null;
+    this.maxValue = null;
+
+    this.stack[this.stack.length] = number;
+  }
+
+  getMin() {
+    if (this.minValue) return this.minValue;
+
+    let min = this.stack[0];
+    let start = 1;
+    let end = this.stack.length;
+
+    while (start <= end) {
+      if (this.stack[start] < min) {
+        min = this.stack[start];
+      }
+
+      if (this.stack[end] < min) {
+        min = this.stack[end];
+      }
+
+      start += 1;
+      end -= 1;
+    }
+
+    this.minValue = min;
+
+    return this.minValue;
+  }
+
+  getMax() {
+    if (this.maxValue) return this.maxValue;
+
+    let max = this.stack[0];
+    let start = 1;
+    let end = this.stack.length;
+
+    while (start <= end) {
+      if (this.stack[start] > max) {
+        max = this.stack[start];
+      }
+
+      if (this.stack[end] > max) {
+        max = this.stack[end];
+      }
+
+      start += 1;
+      end -= 1;
+    }
+
+    this.maxValue = max;
+
+    return this.maxValue;
+  }
+}
+
+exports.MinMaxStack = MinMaxStack;

src/min-max-stack-construction/min-max-stack-construction.test.js

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+import { MinMaxStack } from "./min-max-stack-construction";
+
+function testMinMaxPeek(min, max, peek, stack) {
+  expect(stack.getMin()).toEqual(min);
+  expect(stack.getMax()).toEqual(max);
+  expect(stack.peek()).toEqual(peek);
+}
+
+it("Test Case #1", function () {
+  const stack = new MinMaxStack();
+  stack.push(5);
+  testMinMaxPeek(5, 5, 5, stack);
+  stack.push(7);
+  testMinMaxPeek(5, 7, 7, stack);
+  stack.push(2);
+  testMinMaxPeek(2, 7, 2, stack);
+  expect(stack.pop()).toEqual(2);
+  expect(stack.pop()).toEqual(7);
+  testMinMaxPeek(5, 5, 5, stack);
+});