Two Sum

Given:

Array of integers and a target

Output:

Find two indices where array elements sum is equals to target

Intuition:

Use HashMaps in Java to simplify the solution, I check the difference of the target-current array element value in map and then check if the map already contains a key with difference. If yes, return the index of the difference element and current element in an integer array, else put the current element into map with index i.

Solution:

{

Map<Integer, Integer> map = new HashMap<>();

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

int curr = nums[i];

int diff = target - curr;

if(map.containsKey(diff)){

return new int[] { map.get(diff), i };

}

map.put(curr, i);

}

return null;

}