15 三数之和-蒲公英云

15 三数之和

超时的代码，我不咋会优化，请大神指教

class Solution {
    public static List<List<Integer>> threeSum(int[] nums) {
        List<List<Integer>> numsR = new ArrayList<List<Integer>>();
        List<Integer> intList;
        int zeroSign = 0;
        for(int i = 0 ;i < nums.length ;i++) {
            for(int j = 0 ; j < i ; j ++) {
                for(int k = 0 ; k < j ; k++ ) {
                    if(nums[i]+nums[j]+nums[k]==0) {
                        intList = new ArrayList<Integer>();
                        intList.add(nums[i]);
                        intList.add(nums[j]);
                        intList.add(nums[k]);
                        if(nums[i]==0&&nums[j]==0&&nums[k]==0&&zeroSign==0) {
                            numsR.add(intList);
                            zeroSign+=1;
                            continue;
                        }
                        if(hasEqual(numsR, intList)) continue;
                        else {
                            numsR.add(intList);
                        }
                    }
                }
            }
        }
        return numsR;
    }
    public static boolean hasEqual(List<List<Integer>> basic , List<Integer> list) {
        Iterator<List<Integer>> listinfo = basic.iterator();
        List<Integer> buffer ;
        while(listinfo.hasNext()) {
            buffer = listinfo.next();
            if(buffer.containsAll(list)) return true;
        }
        return false;
    }
}