leetcode-1-easy

思路一:暴力求解

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

        return new int[2];
    }

思路二:利用 map 存储下标，如果 target - nums[i] 存在，说明解已经求得

    public int[] twoSum(int[] nums, int target) {
        Map<Integer, Integer> map = new HashMap<>();

        for (int i = 0; i < nums.length; i++) {
            if (map.containsKey(target - nums[i])) {
                return new int[]{map.get(target - nums[i]), i};
            }
            map.put(nums[i], i);
        }

        return new int[2];
    }