TwoSum.java

package easy;

import java.util.HashMap;
import java.util.Map;

public class TwoSum {
    public int[] twoSum_ON2(int[] nums, int target) {
        int[] result = new int[2];
        for(int i = 0; i < nums.length-1; i++){
            for(int j = i+1; j < nums.length; j++){
                if(nums[i] + nums[j] == target){
                    result[0] = i;
                    result[1] = j;
                    break;
                }
            }
        }
        return result;
    }
    
    public int[] twoSum_ON(int[] nums, int target) {
        Map<Integer, Integer> map = new HashMap();
        int[] result = new int[2];
        for(int i = 0; i < nums.length; i++){
            if(map.containsKey(target-nums[i])){
                result[0] = map.get(target-nums[i]);
                result[1] = i;
                break;
            } else {
                map.put(nums[i], i);
            }
        }
        return result;
    }
}