1. 两数之和.md

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