lessfish / leetcode Goto Github PK

    public List<List<Integer>> threeSum(int[] nums) {
        
        List<Integer> list;
        List<List<Integer>> retList = new  LinkedList<>();
        Arrays.sort(nums);
        for( int i = 0; i < nums.length && nums[i] <= 0; i++){
            if( i > 0 && nums[i] == nums[i-1])
                continue;
            int sum = (-1)*nums[i], front = i + 1, behin = nums.length - 1;
            while( front < behin )
                if( nums[front] + nums[behin] > sum) 
                    behin--;
                else if( nums[front] + nums[behin] < sum) 
                    front++;
                else{
                    list = new LinkedList<Integer>();
                    list.add(nums[i]);
                    list.add(nums[front]);
                    list.add(nums[behin]);
                    retList.add(list);
                    while( front<behin && nums[front]==nums[front+1]) front++;
                    while( front<behin && nums[behin]==nums[behin-1]) behin--;
                    front++;
                    behin--;
                }
        }
        return retList;
    }

func isValid(s string) bool {
	if len(s)%2 != 0 {
		return false
	}
	left := map[byte]struct{}{
		'(': struct{}{},
		'[': struct{}{},
		'{': struct{}{},
	}
	right := map[byte]struct{}{
		')': struct{}{},
		']': struct{}{},
		'}': struct{}{},
	}
	bytes := []byte(s)
	stack := []byte{}
	for i := range bytes {
		if _, ok := left[bytes[i]]; ok {
			stack = append(stack, bytes[i])
		} else if _, ok = right[bytes[i]]; ok {
			if len(stack) == 0 {
				return false
			}
			switch stack[len(stack)-1] {
			case '(':
				if bytes[i] != ')' {
					return false
				}
			case '[':
				if bytes[i] != ']' {
					return false
				}
			case '{':
				if bytes[i] != '}' {
					return false
				}
			}
			stack = stack[:len(stack)-1]
		} else {
			return false
		}
	}
	if len(stack) == 0 {
		return true
	}
	return false
}