LeetCode:15 三数之和（双指针）

class Solution {
    public List<List<Integer>> threeSum(int[] nums) {
        List<List<Integer>> res = new ArrayList<>();
        int len = nums.length;
        Arrays.sort(nums);
        int left,right;
        int ans=0;
        for(int i=0;i<len;i++){
            left=i+1;
            right=len-1;
            ans = nums[i];
            if(i!=0&&nums[i]==nums[i-1]){
                continue;
            }
            while(left<right){
                if(left!=(i+1)&&nums[left]==nums[left-1]){
                    left++;
                    continue;
                }
                if((ans+nums[left]+nums[right])==0){
                    List<Integer>a = new ArrayList<Integer>();
                    a.add(ans);
                    a.add(nums[left]);
                    a.add(nums[right]);
                    res.add(a);
                    left++;right--;
                    continue;
                }
                if((ans+nums[left]+nums[right])>0){
                    right--;
                    continue;
                }
                if((ans+nums[left]+nums[right])<0){
                    left++;
                    continue;
                }
            }
        }
        return res;       
    }
}