[Easy] 1. Two Sum

雙for loop寫法

    public int[] twoSum(int[] nums, int target) {
        int ans[] = new int[2];
        for(int i=0;i<nums.length;i++){
            int tmp = target-nums[i];
            for(int j=0;j<nums.length;j++){
                if(j!=i&&nums[j]==tmp){
                    ans[0]=i;
                    ans[1]=j;
                    break;
                }
            }    
        }
        
        return ans;
    }

Map寫法

    public int[] twoSum(int[] nums, int target) {
        HashMap<Integer,Integer> map = new HashMap();
        int ans[] = new int[2];
        for(int i=0;i<nums.length;i++){
            int diff = target-nums[i];            
            if(map.containsKey(diff)){               
                ans[0] = map.get(diff);
                ans[1] = i;
                break;
            }else{
                map.put(nums[i],i);
            }
        }
       
        return ans;
    }