Update docs with disppeared number and identical pairs problems

Author: sudheerj

README.md

@@ -61,6 +61,8 @@ List of Programs related to data structures and algorithms
 | 20  | Majority Element                 |        [Source](https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/20.majorityElement/majorityElement.js)        | [JavaScript](https://livecodes.io/?console=open&x=https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/20.majorityElement/majorityElement.js)               |        [Documentation](https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/20.majorityElement/majorityElement.md)        | Easy | Boyer Moore Voting algorithm |
 | 21  | Pivot Index                |        [Source](https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/21.pivotIndex/pivotIndex.js)        | [JavaScript](https://livecodes.io/?console=open&x=https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/21.pivotIndex/pivotIndex.js)               |        [Documentation](https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/21.pivotIndex/pivotIndex.md)        | Easy | Array traversal |
 | 22  | Range Sum queries                |        [Source](https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/22.sumRange/sumRange.js)        | [JavaScript](https://livecodes.io/?console=open&x=https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/22.sumRange/sumRange.js)               |        [Documentation](https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/22.sumRange/sumRange.md)        | Easy | Array traversal |
+| 23  | Disappeared numbers                |        [Source](https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/23.disappearedNumbers/disappearedNumbers.js)        | [JavaScript](https://livecodes.io/?console=open&x=https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/23.disappearedNumbers/disappearedNumbers.js)               |        [Documentation](https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/23.disappearedNumbers/disappearedNumbers.md)        | Easy | Array traversal |
+| 24  | Identical pairs                |        [Source](https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/24.identicalPairs/identicalPairs.js)        | [JavaScript](https://livecodes.io/?console=open&x=https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/24.identicalPairs/identicalPairs.js)               |        [Documentation](https://github.com/sudheerj/datastructures-algorithms/blob/master/src/javascript/algorithms/array/24.identicalPairs/identicalPairs.md)        | Easy | Array traversal & map |
 
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