leetcode solutions added

Author: mrinaljain

A/array-methods/array_methods.md

@@ -1,25 +1,37 @@
 # [Array Methods](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array)
 
-### map
-Map takes an array and performes certain operations on it and then returns a new array.
+
+### copyWithin
+copy elements within the array
+```
+copyWithin(target, start)
+copyWithin(target, start, end)
+copy to targetIndex from startIndex to endIndex
+```
+
+### every
+Checks if every element folows the given function and returns 1 boolean value
+```
+```
+
+### forEach
+forEach runs a function on each value of the array and returns nothing
+```
+arr.forEach(item => console.log(item));
+```
+
 
 ### filter
 Filter returnes some part of the array based on certain condition
 
-### reduce
-reduce will work on the entire array and return the resultant
+### fill
+fill value in array from startIndex to End index
 ```
-Array.reduce(callback, initialValue)
+fill(value)
+fill(value, start)
+fill(value, start, end)
 
-function callback(previousValue , currentValue , currentIndex, arr){
-   .
-   .
-   .
-   return currentValue;
-}
 ```
-### reduceRight
-reduceRight works from right to left
 
 ### Find
 Find will iterate through all items of array and return the first  item that matches the condition given inside callback function.
@@ -40,6 +52,13 @@ arr.findIndex(callback(value, index, obj));
 returns first matching index or -1
 ```
 
+
+### flat
+returns the flat version of the multi level array.
+```
+```
+
+
 ### lastIndexOf
 returns the last occurance of the given item
 
@@ -52,6 +71,28 @@ length will return the length of the given array.
 ```
 ```
 
+
+### map
+Map takes an array and performes certain operations on it and then returns a new array.
+
+
+### reduce
+reduce will work on the entire array and return the resultant
+```
+Array.reduce(callback, initialValue)
+
+function callback(previousValue , currentValue , currentIndex, arr){
+   .
+   .
+   .
+   return currentValue;
+}
+```
+### reduceRight
+reduceRight works from right to left
+
+
+
 ### isArray()
 ```
 Array.isArray(arr);
@@ -60,12 +101,7 @@ Array.isArray(arr);
 ### reverse
 reverse method will return the array with reversed index on th esame array.
 
-### sort 
-sort will sort the array lexically and return the updated array.
-- sort method can take another param that is a comparator
-```
-Array.sort(comparator);
-```
+
 
 
 ### join
@@ -81,22 +117,12 @@ Note: takes no parameter
 
 ```
 
-### flat
-returns the flat version of the multi level array.
-```
-```
-
 ### includes
 includes takes a key and returnd TRUE or FALSE based upon presence of that key in array.
 also takes starting index to search from
 ```
 arr.includes(searchElement, fromIndex): boolean
 
-```
-### forEach
-forEach runs a function on each value of the array and returns nothing
-```
-arr.forEach(item => console.log(item));
 ```
 
 ### shift
@@ -141,40 +167,14 @@ returns iterator which contains array in which key value is present
 ```
 ```
 
-### splice
-used to add/ remove few elements from the array.
-**start** : An integer from were the pprocess neeeds to be started
-**deleteCount** : An integer indicating the number of elements in the array to remove from start.
-```
-splice(start)
-splice(start, deleteCount)
-splice(start, deleteCount, item1, item2, /* …, */ itemN)
-```
-
-
-### slice
-returns subpart of array 
- - Start to End (end not included)
- - Negative index counts back from the end of the array
-```
-slice()
-slice(start)
-slice(start, end)
-```
----
-## *Adverbs*
 
 
 ### of
 creates a new array with whatever comma seperated values are provided.
 ```
 let arr = Array.of("2", 5);
 ```
----
-### every
-Checks if every element folows the given function and returns 1 boolean value
-```
-```
+
 ### some
 Checks if EVEN ONE element folows the given function and returns 1 boolean value
 ```
@@ -194,7 +194,6 @@ Array.from(arrayLike, mapFn, thisArg)
 returns item at that particular index
 ```
 ```
----
 
 ### flatMap
 It is identical to a map() followed by a flat() of depth **1**(arr.map(...args).flat())
@@ -204,20 +203,62 @@ flatMap(callbackFn, thisArg)
 
 ```
 
-### fill
-fill value in array from startIndex to End index
+
+
+### splice
+- same array ko update krdega.
+used to add / remove / replace few elements from the array.
+**It modifies the original array**
+*returnType* : **returns an array containing the removed elements (if any)**
+
+**start** : An integer from were the process neeeds to be started
+**deleteCount** : An integer indicating the number of elements in the array to remove from start.
+**items** : items to be inserted
 ```
-fill(value)
-fill(value, start)
-fill(value, start, end)
+splice(start) // Removes everything from index start onwards
+splice(start, deleteCount)
+splice(start, deleteCount, item1, item2, /* …, */ itemN)
+```
+1. orignal array ko modify karega
+2. return kata hua ya jo remove kr reh ho vo part karega.
+3. sirf start doge to startIndex se array end tak sab gayab kr dega.
+4. jo items add hoti hai vo startIndex se hi add hona chalu hoti hai.
+5. Remove all elements of array
+```
+arr.splice(0, arr.length);
+``` 
+
 
+### slice 
+
+ .slice() method is used to extract a portion of an array (or string) without modifying the original array
 ```
-### copyWithin
-copy elements within the array
+slice()  // No Slicing, just creates a copy of Array.
+slice(start) // default value of end is last index
+slice(start, end) // start to end-1 index
+
 ```
-copyWithin(target, start)
-copyWithin(target, start, end)
-copy to targetIndex from startIndex to endIndex
+1. Array kaat ke ney array deta hai.
+2. Existing Array ko kuch nahi hoga.
+3. returns subpart of array 
+   - Start to End (*end not included*)
+4. Negative index counts back from the end of the array
+   - **-1 refers to the last element**
+   ```
+   slice (-1) 
+   // -1 is startIndex 
+   // endIndex not given so last index is equal to end Index by default and is baar end index ki value bhi include hogi.
+   ```
+5. Remember important thing agar end index doge to end index pr jo value hai vo include nahi hogi, aur agar end index nahi doge to startIndex se last index tak ka array return milega.
+6. if start === end then returns empty array 
+7. OR in simple words if endIndex <= startIndex then return empty array.
+
+
+### sort 
+sort will sort the array lexically and return the updated array.
+- sort method can take another param that is a comparator
+```
+Array.sort(comparator);
 ```
 
 

A/array-methods/slice.js

@@ -1,7 +1,47 @@
 const arr = ["ant", "bison", "camel", "duck", "elephant"];
 
+
+
 // slice(start, end)
-let one  = arr.slice();
+let ans = arr.slice(0, 2);
+console.log("Sliced Array", ans);
+console.log("Original Array", arr);
+console.log("Original Array remains the same");
+
+// slice()
+let ans2 = arr.slice();
+console.log(ans2);
+
+// slice(start)
+let ans3 = arr.slice(1);
+console.log(ans3);
+
+// negative index
+let ans4 = arr.slice(-1);
+console.log(ans4);
+
+// negative start index
+let ans5 = arr.slice(-3);
+let ans6 = arr.slice(-3, 4);
+
+console.log(ans5);
+console.log(ans6);
+
+// negative end index
+let ans7 = arr.slice(3, -2);
+
+console.log(ans7);
+
+// start is equal to end
+let ans8 = arr.slice(3, 3);
+
+console.log(ans8);
+
+
+//Both Start and End as Negative Values
 
-console.log(one);
+let ans9 = arr.slice(-2, -4);
+let ans10 = arr.slice(-4, -2);
 
+console.log("ans9", ans9); // "camel", "duck"
+console.log("ans10", ans10); // "bison", "camel"

A/array-methods/splice.js

@@ -2,13 +2,26 @@
 splice(start, deleteCount);
 splice(start, deleteCount, item1, item2,  itemN) */
 
-const months = ["Jan", "March", "April", "June", "July"];
+const months = ["Jan", "bef", "March", "April", "May", "June", "July"];
 
-months.splice(3 , 2 , "change", "another");
-console.log(months);
+//! Removing elements
+
+//? splice for only removing
+// months.splice(4, 1);
+
+//! Adding elements
+
+//? Remove + Add  splice(start, deleteCount, item1, item2,  itemN)
+// let ans = months.splice(3 , 2 , "change", "another");
+// console.log(ans);
 
+//! Replacing Elements
+
+months.splice(1, 1, "Feb");
+
+console.log(months);
 
-months.splice(4, 1, 'May');
-// Replaces 1 element at index 4
+//! using negative index
 
-// console.log(months);
+//! removing all elements
+// arr.splice(0, arr.length);

C/classes/README.md

@@ -0,0 +1,14 @@
+# Classes
+
+
+private variables in class  ( using #)
+```
+class ClassName{
+   #varName;
+
+   constructor(){
+      this.#varName = value;
+   }
+
+}
+```

O/object-methods/README.md

@@ -17,4 +17,10 @@ object.hasOwnProperty()
 
 
 
-"propertyName" in Object   // checks if property is present in object
+"propertyName" in Object   // checks if property is present in object
+
+## delete a key
+
+```
+delete obhect.key;
+```

O/oops/readme.md

@@ -2,4 +2,6 @@
 
 A constructor function in JavaScript is a special type of function used to create and initialize objects. 
 
-// ES 6 introduced concept of  classes which is same as the constructor functions , just a syntactical sugar
+// ES 6 introduced concept of  classes which is same as the constructor functions , just a syntactical sugar
+
+

machine-coding/index.html

@@ -17,14 +17,7 @@
     </style>
   </head>
   <body>
-    <script src="./solutions/one.js"></script>
-
-    <div class="list" >
-      <input type="checkbox" name="parent" value="value" id="" />
-      <input type="checkbox" name="parent" value="value" id="" />
-      <input class="child" type="checkbox" name="parent" value="value" id="" />
-      <input type="checkbox" name="parent" value="value" id="" />
-      <input type="checkbox" name="parent" value="value" id="" />
-    </div>
+    
+    <script src="./lru-cache.js"></script>
   </body>
 </html>