searching algorithms

DSA/searching-algorithms/README.md

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+# Searching Algorithms
+
+* Searching Algorithms are designed to check for an element or retrieve an element from any data structure where it is stored.
+
+## [Linear Search](linear-search.js)
+* The list or array is traversed sequentially and every element is checked.
+
+## [Binary Search](binary-search.js)
+* Binary Search is a searching algorithm used in a sorted array by repeatedly dividing the search interval in half.
+* The idea of binary search is to use the information that the array is sorted and reduce the time complexity to O(Log n).
+
+## The basic steps to perform Binary Search are:
+    * Begin with an interval covering the whole array.
+    * If the value of the search key is less than the item in the middle of the interval, narrow the interval to the lower half.
+    * Otherwise, narrow it to the upper half.
+    * Repeatedly check until the value is found or the interval is empty.

DSA/searching-algorithms/binary-search.js

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+/**
+ * Given a sorted array if integers, write a function called search, that accepts a value and returns the index where the value passed to the function is located.
+ * If the value is not found, return -1;
+ */
+
+function search(arr, n) {
+    let left = 0;
+    let right = arr.length - 1;
+
+    while(left <= right) {
+        const mid = Math.floor((left + right) / 2);
+        if(arr[mid] === n) {
+            return mid;
+        }
+        if(arr[mid] < n) {
+            left = mid+1;
+        } else {
+            right = mid - 1;
+        }
+    }
+    return -1;
+}
+
+// const result = search([1,2,3,4,5,6], 4); // 3
+// const result = search([1,2,3,4,5,6], 6); // 5
+// const result = search([1,2,3,4,5,6], 11); // -1
+// console.log(result);

DSA/searching-algorithms/linear-search.js

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+/**
+ * Linear Search
+ * Given an array arr[] of n elements, write a function to search a given element val in arr[].
+ */
+
+function linearSearch(arr, val) {
+    for(let i =0; i<arr.length; i++) {
+        if(arr[i] === val) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+// const result = linearSearch([1,2,4,7,3], 7);
+// const result = linearSearch([1,2,4,7,3], 5);
+// console.log(result);