LeetCode热题 首题 两数之和

class Solution {
    public int[] twoSum(int[] nums, int target) {
        int[] result = new int[2];
        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){
                    result[0]=i;
                    result[1]=j;
                    break;
                }
            }
        }
        return result;
    }
}

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