01.twoSum

// Better in O(nlogn)
class Solution {
    public int[] twoSum(int[] nums, int target) {
    Map<Integer,Integer> map=new HashMap<>();
    for(int i=0;i<nums.length;i++){
        int diff=target-nums[i];
        if(map.containsKey(diff)){
            return new int[] {map.get(diff), i};

        }
        map.put(nums[i],i);
    }
    return new int[] {-1,-1};
    }
}

// Brute in O(n^2)

class Solution {
    public int[] twoSum(int[] nums, int target) {
        int n=nums.length;
        for(int i=0;i<n;i++){
            for(int j=i+1;j<n;j++){
                if(nums[i]+nums[j]==target){
                    return new int[] {i,j};
                }
            }
        }
        return new int[] {};
    }
}