Merge branch 'master' of https://github.com/Narahari-Sundaragopalan/JavaScript-Interview-Questions

Author: Narahari-Sundaragopalan

concepts/Currying.md

@@ -131,4 +131,4 @@ const sum = a => {
 
 // Simplified to one line
 const sum = a => b => b ? sum(a + b) : a;
-```
+```

exercises/leetcode/groupAnagrams.js

@@ -32,4 +32,10 @@ const groupAnagrams = strs => {
 	}
 
 	return Array.from(anagramMap.values());
-}
+}
+
+/**
+ * Time Complexity: O(NKlogK) - Outer Loop : O(N) and string sort O(KlogK) where K is max length
+ * of a string in strs
+ * Space Complexity: O(NK) (N elements with string of size K stored ?)
+ */

exercises/leetcode/rotateImage.js

@@ -0,0 +1,57 @@
+/**
+ * You are given an n x n 2D matrix representing an image.
+
+Rotate the image by 90 degrees (clockwise).
+
+Note:
+
+You have to rotate the image in-place, which means you have to modify the 
+input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.
+
+Example 1:
+
+Given input matrix = 
+[
+  [1,2,3],
+  [4,5,6],
+  [7,8,9]
+],
+
+rotate the input matrix in-place such that it becomes:
+[
+  [7,4,1],
+  [8,5,2],
+  [9,6,3]
+]
+Example 2:
+
+Given input matrix =
+[
+  [ 5, 1, 9,11],
+  [ 2, 4, 8,10],
+  [13, 3, 6, 7],
+  [15,14,12,16]
+], 
+
+rotate the input matrix in-place such that it becomes:
+[
+  [15,13, 2, 5],
+  [14, 3, 4, 1],
+  [12, 6, 8, 9],
+  [16, 7,10,11]
+]
+ */
+
+const rotate = matrix => {
+    const step = matrix.length - 1;
+
+    for (let i = 0; i < (matrix.length / 2); i++) {
+        for (let j = 0; j < (matrix.length - 1) / 2; j++) {
+            let temp = matrix[i][j];
+            matrix[i][j] = matrix[step - j][i];
+            matrix[step - j][i] = matrix[step - i][step - j];
+            matrix[step - i][step - j] = matrix[j][step - i];
+            matrix[j][step - i] = temp;
+        }
+    }
+}

exercises/leetcode/validParenthesis.js

@@ -34,4 +34,8 @@ const validParenthesis = str => {
 	}
 
 	return strStack.length === 0;
-}
+}
+/**
+ * Time Complexity: O(n)
+ * Space Complexity: O(n)
+ */

exercises/strings/reverseEachWord.js

@@ -65,6 +65,11 @@ var reverseWords = function(s) {
     return s.split(/\s+/).reverse().join(' ').trim();
 };
 
+/**
+ * Time Complexity: O(N)
+ * Space Complexity: O(N)
+ */
+
 /**
  * Without using built in functions
  * @param {string} s 

exercises/strings/reverseString2.js

@@ -30,15 +30,20 @@ const reverseEachWord = str => {
         while(end < n && str[end] !== ' ') {
             end++;
         }
-        reverse(str, start, end);
+        reverse(str, start, end - 1);
         start = end + 1;
         end++;
     }
 }
 
 const reverseWords = s => {
     // reverse the string
-    s = reverse(s, 0, s.length - 1);
+    reverse(s, 0, s.length - 1);
     // reverse each word
     reverseEachWord(s);
-}
+}
+
+/**
+ * Time Complexity: O(N);
+ * Space Complexity: O(1);
+ */