add: time complexity examples in js

data_structures/README.md

@@ -10,6 +10,7 @@ This section contains Data Structure and Algorithms in Java, Typescript and Fron
 - [Prefix](./src/KeyPatterns/Prefix/README.md)
 - [NeetCode 150](./neetcode_150/)
 - [Javascript Questions](./js_questions)
+- [Time and Space Complexity](./time_space_complexity/README.md)
 
 ## Docs
 

data_structures/time_space_complexity/README.md

@@ -0,0 +1,9 @@
+# Time and Space Complexity
+
+## Time Complexity
+
+- Measures how the execution time of an algorithm increases with input size (n)
+
+## Space Complexity
+
+- Measures how much memory an algorithm needs as input size (n) increases.

data_structures/time_space_complexity/time_complexity/constant_time.js

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+/**
+ * Constant Time - 0(1)
+ * @description
+ * - Time doesn't depend on input size
+ * @param {number[]} arr
+ */
+function getFirstElement(arr) {
+  return arr[0];
+}
+console.log(getFirstElement([1, 2, 3]));

data_structures/time_space_complexity/time_complexity/linear_time.js

@@ -0,0 +1,12 @@
+/**
+ * Linear Time - O(n)
+ * @description
+ * - Time grows proportionally with input size
+ * @param {number[]} arr
+ */
+function printAll(arr) {
+  for (let i = 0; i < arr.length; i++) {
+    console.log('arr --> ', arr[i]);
+  }
+}
+printAll([1, 2, 3]);

data_structures/time_space_complexity/time_complexity/logarithmic_time.js

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+/**
+ * Logarithmic Time - O(log n)
+ * @param {number[]} arr
+ * @param {number} target
+ * @returns {number}
+ */
+function binarySearch(arr, target) {
+  let left = 0,
+    right = arr.length - 1;
+
+  while (left <= right) {
+    let mid = Math.floor((left + right) / 2);
+    if (arr[mid] === target) return mid;
+    arr[mid] < target ? (left = mid + 1) : (right = mid - 1);
+  }
+  return -1;
+}
+
+const result = binarySearch([1, 3, 5, 7, 9], 5);
+console.log('result', result);

data_structures/time_space_complexity/time_complexity/quadratic_time.js

@@ -0,0 +1,14 @@
+/**
+ * Quadratic Time - O(n²)
+ * @description
+ * - Nested Loops cause exponential growth.
+ * @param {number[]} arr
+ */
+function printPair(arr) {
+  for (let i = 0; i < arr.length; i++) {
+    for (let j = 0; j < arr.length; j++) {
+      console.log(arr[i], arr[j]);
+    }
+  }
+}
+printPair([1, 2, 3, 4, 5, 6]);