package LinkedInQuestions;

import java.util.HashMap;

import java.util.Map;

/**

* Created by ranjan on 7/24/16.

* Design and implement a TwoSum class. It should support the following operations: add and find.

add(input) – Add the number input to an internal data structure.

find(value) – Find if there exists any pair of numbers which sum is equal to the value.

*/

public class TwoSumFind {

private Map<Integer, Integer> table = new HashMap<>();

HashMap<Integer, Integer> hm = new HashMap<>();

public void add(int input){

int count = table.containsKey(input)?table.get(input):0;

table.put(input,count+1);

}

public boolean find(int val){

for(Map.Entry<Integer,Integer> entry: table.entrySet()){

int num = entry.getKey();

int y = val - num;

if(y==num){

if(entry.getValue()>=2){

return true;

} else if(table.containsKey(y)){

return true;

}

}

}

return false;

}

/*

Second Solution working

*/

public void two_sum_prob_sum(int arr[]) {

for (int i = 0; i < arr.length; i++) {

hm.put(arr[i], arr[i]);

}

}

public void two_sum_prob_find(int arr[], int sum){

for(int i = 0; i<arr .length;i++){

int lookFor = sum-arr [i];

boolean hasValue = hm.containsValue(lookFor);

if(hasValue){

System.out.println("Found: "+arr[i]+"+"+ lookFor + "="+sum);

}

}

}

public static void main(String[] args){

TwoSumFind tsw = new TwoSumFind();

tsw.add(11);

tsw.add(3);

tsw.add(5);

tsw.add(9);

System.out.println(tsw.find(20));

int[] arr = {1,3,5,9};

int sum = 8;

tsw.two_sum_prob_sum(arr);

tsw.two_sum_prob_find(arr,sum);;

}

}