Java Solution, 3 pointers


  • 6

    Same as https://leetcode.com/problems/3sum-closest

    Assume a is the longest edge, b and c are shorter ones, to form a triangle, they need to satisfy len(b) + len(c) > len(a).

    public class Solution {
        public int triangleNumber(int[] nums) {
            int result = 0;
            if (nums.length < 3) return result;
            
            Arrays.sort(nums);
    
            for (int i = 2; i < nums.length; i++) {
                int left = 0, right = i - 1;
                while (left < right) {
                    if (nums[left] + nums[right] > nums[i]) {
                        result += (right - left);
                        right--;
                    }
                    else {
                        left++;
                    }
                }
            }
            
            return result;
        }
    }
    

  • 0

    smart! Thank you!


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