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  • LeetCode 1. Two Sum
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  • LeetCode 9. Palindrome Number
  • LeetCode 10. Regular Expression Matching
  • LeetCode 11. Container With Most Water
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  • LeetCode 14. Longest Common Prefix
  • LeetCode 15. 3Sum
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  • LeetCode 17. Letter Combinations of a Phone Number
  • LeetCode 18. 4Sum
  • LeetCode 19. Remove Nth Node From End of List
  • LeetCode 20. Valid Parentheses
  • LeetCode 21. Merge Two Sorted Lists
  • LeetCode 22. Generate Parentheses
  • LeetCode 23. Merge k Sorted Lists
  • LeetCode 24. Swap Nodes in Pairs
  • LeetCode 25. Reverse Nodes in k-Group
  • LeetCode 26. Remove Duplicates from Sorted Array
  • LeetCode 27. Remove Element
  • LeetCode 28. Implement strStr()
  • LeetCode 29. Divide Two Integers
  • LeetCode 30. Substring with Concatenation of All Words
  • LeetCode 31. Next Permutation
  • LeetCode 32. Longest Valid Parentheses
  • LeetCode 33. Search in Rotated Sorted Array
  • LeetCode 42. Trapping Rain Water
  • LeetCode 56. Merge Intervals
  • LeetCode 67. Add Binary
  • LeetCode 81. Search in Rotated Sorted Array II
  • LeetCode 124. Binary Tree Maximum Path Sum
  • LeetCode 125. Valid Palindrome
  • LeetCode 153. Find Minimum in Rotated Sorted Array
  • LeetCode 154. Find Minimum in Rotated Sorted Array II
  • LeetCode 157. Read N Characters Given Read4
  • LeetCode 158. Read N Characters Given Read4 II - Call multiple times
  • LeetCode 236. Lowest Common Ancestor of a Binary Tree
  • LeetCode 238. Product of Array Except Self
  • LeetCode 269. Alien Dictionary
  • Leetcode 295. Find Median from Data Stream
  • Leetcode 297. Serialize and Deserialize Binary Tree
  • LeetCode 300. Longest Increasing Subsequence
  • LeetCode 301. Remove Invalid Parentheses
  • LeetCode 336. Palindrome Pairs
  • LeetCode 407. Trapping Rain Water II
  • LeetCode 415. Add Strings
  • LeetCode 426. Convert Binary Search Tree to Sorted Doubly Linked List
  • LeetCode 489. Robot Room Cleaner
  • LeetCode 560. Subarray Sum Equals K
  • LeetCode 680. Valid Palindrome II
  • LeetCode 710. Random Pick with Blacklist
  • LeetCode 721. Accounts Merge
  • LeetCode 863. All Nodes Distance K in Binary Tree
  • LeetCode 918. Maximum Sum Circular Subarray
  • LeetCode 953. Verifying an Alien Dictionary
  • LeetCode 973. K Closest Points to Origin
  • LeetCode 1249. Minimum Remove to Make Valid Parentheses
  • LeetCode 1428. Leftmost Column with at Least a One
  • LeetCode 1570. Dot Product of Two Sparse Vectors
  • LeetCode 1644. Lowest Common Ancestor of a Binary Tree II
  • LeetCode 1650. Lowest Common Ancestor of a Binary Tree III
  • LeetCode 1676. Lowest Common Ancestor of a Binary Tree IV
  • Leetcode 1727. Largest Submatrix With Rearrangements
  • LeetCode 1751. Maximum Number of Events That Can Be Attended II
  • LeetCode 1754. Largest Merge Of Two Strings
  • LeetCode 1755. Closest Subsequence Sum
  • LeetCode 1760. Minimum Limit of Balls in a Bag
  • LeetCode 1761. Minimum Degree of a Connected Trio in a Graph
  • LeetCode 1764. Form Array by Concatenating Subarrays of Another Array
  • LeetCode 1765. Map of Highest Peak
  • LeetCode 1766. Tree of Coprimes
  • LeetCode 1770. Maximum Score from Performing Multiplication Operations
  • LeetCode 1771. Maximize Palindrome Length From Subsequences
  • LeetCode 1774. Closest Dessert Cost
  • LeetCode. 1775 Equal Sum Arrays With Minimum Number of Operations
  • LeetCode 1776. Car Fleet II
  • LeetCode 1778. Shortest Path in a Hidden Grid
  • LeetCode 1779. Find Nearest Point That Has the Same X or Y Coordinate
  • LeetCode 1780. Check if Number is a Sum of Powers of Three
  • LeetCode 1781. Sum of Beauty of All Substrings
  • LeetCode 1782. Count Pairs Of Nodes
  • LeetCode 1784. Check if Binary String Has at Most One Segment of Ones
  • LeetCode 1785. Minimum Elements to Add to Form a Given Sum
  • LeetCode 1786. Number of Restricted Paths From First to Last Node
  • LeetCode 1787. Make the XOR of All Segments Equal to Zero
  • LeetCode 1788. Maximize the Beauty of the Garden
  • LeetCode 1790. Check if One String Swap Can Make Strings Equal
  • LeetCode 1791. Find Center of Star Graph
  • LeetCode 1792. Maximum Average Pass Ratio
  • LeetCode 1793. Maximum Score of a Good Subarray
  • LeetCode 1794. Count Pairs of Equal Substrings With Minimum Difference
  • LeetCode 1796. Second Largest Digit in a String
  • LeetCode 1797. Design Authentication Manager
  • LeetCode 1798. Maximum Number of Consecutive Values You Can Make
  • LeetCode 1799. Maximize Score After N Operations
  • LeetCode 1800. Maximum Ascending Subarray Sum
  • LeetCode 1801. Number of Orders in the Backlog
  • LeetCode 1802. Maximum Value at a Given Index in a Bounded Array
  • LeetCode 1803. Count Pairs With XOR in a Range
  • LeetCode 1804. Implement Trie II (Prefix Tree)
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  • LeetCode 1807. Evaluate the Bracket Pairs of a String
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  • LeetCode 1810. Minimum Path Cost in a Hidden Grid
  • LeetCode 1812. Determine Color of a Chessboard Square
  • LeetCode 1813. Sentence Similarity III
  • LeetCode 1814. Count Nice Pairs in an Array
  • LeetCode 1815. Maximum Number of Groups Getting Fresh Donuts
  • LeetCode 1816. Truncate Sentence
  • LeetCode 1817. Finding the Users Active Minutes
  • LeetCode 1818. Minimum Absolute Sum Difference
  • LeetCode 1819. Number of Different Subsequences GCDs
  • LeetCode 1820. Maximum Number of Accepted Invitations
  • LeetCode 1822. Sign of the Product of an Array
  • LeetCode 1824. Minimum Sideway Jumps
  • LeetCode 1825. Finding MK Average
  • LeetCode 1826. Faulty Sensor
  • LeetCode 1827. Minimum Operations to Make the Array Increasing
  • LeetCode 1828. Queries on Number of Points Inside a Circle
  • LeetCode 1829. Maximum XOR for Each Query
  • LeetCode 1830. Minimum Number of Operations to Make String Sorted
  • LeetCode 1832. Check if the Sentence Is Pangram
  • LeetCode 1833. Maximum Ice Cream Bars
  • LeetCode 1834. Single-Threaded CPU
  • LeetCode 1835. Find XOR Sum of All Pairs Bitwise AND
  • LeetCode 1836. Remove Duplicates From an Unsorted Linked List
  • LeetCode 1837. Sum of Digits in Base K
  • LeetCode 1839. Longest Substring Of All Vowels in Order
  • LeetCode 1840. Maximum Building Height
  • LeetCode 1847. Closest Room
  • LeetCode 1850. Minimum Adjacent Swaps to Reach the Kth Smallest Number
  • LeetCode 1851. Minimum Interval to Include Each Query
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LeetCode 1761. Minimum Degree of a Connected Trio in a Graph

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Last updated 4 years ago

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You are given an undirected graph. You are given an integer n which is the number of nodes in the graph and an array edges, where each edges[i] = [ui, vi] indicates that there is an undirected edge between ui and vi.

A connected trio is a set of three nodes where there is an edge between every pair of them.

The degree of a connected trio is the number of edges where one endpoint is in the trio, and the other is not.

Return the minimum degree of a connected trio in the graph, or -1 if the graph has no connected trios.

Example 1:

Input: n = 6, edges = [[1,2],[1,3],[3,2],[4,1],[5,2],[3,6]]
Output: 3
Explanation: There is exactly one trio, which is [1,2,3]. The edges that form its degree are bolded in the figure above.

Example 2:

Input: n = 7, edges = [[1,3],[4,1],[4,3],[2,5],[5,6],[6,7],[7,5],[2,6]]
Output: 0
Explanation: There are exactly three trios:
1) [1,4,3] with degree 0.
2) [2,5,6] with degree 2.
3) [5,6,7] with degree 2.

Constraints:

  • 2 <= n <= 400

  • edges[i].length == 2

  • 1 <= edges.length <= n * (n-1) / 2

  • 1 <= ui, vi <= n

  • ui != vi

  • There are no repeated edges.

Solution1:

class Solution {
public:
    int minTrioDegree(int n, vector<vector<int>>& edges) {
        vector<unordered_set<int>> graph(n+1);
        
        for (const vector<int>& edge : edges) {
            graph[edge[0]].insert(edge[1]);
            graph[edge[1]].insert(edge[0]);
        }
        
        int ans = INT_MAX;
        for (int i = 1; i <= n; i++) {
            const unordered_set<int>& neighbors = graph[i];
            int tmp_a = graph[i].size() - 2;
            if (tmp_a >= ans) {
                continue;
            }
            for (int b : neighbors) {
                int tmp_b = tmp_a + graph[b].size() - 2;
                if (b < i || tmp_b >= ans) {
                    continue;
                }
                for (int c : graph[b]) {
                    if (neighbors.count(c) > 0) {
                        ans = min(ans, tmp_b + (int)graph[c].size() - 2);
                    }
                } 
            }
        }
        
        return ans == INT_MAX? -1 : ans;
    }
};

Solution2:

class Solution {
public:
    int minTrioDegree(int n, vector<vector<int>>& edges) {
        vector<vector<bool>> graph(n+1, vector<bool>(n+1, false));
        vector<int> degree(n+1, 0);
        
        for (const vector<int>& edge : edges) {
            graph[edge[0]][edge[1]] = true;
            graph[edge[1]][edge[0]] = true;
            degree[edge[0]]++;
            degree[edge[1]]++;
        }
        
        int ans = INT_MAX;
        for (int i = 1; i <= n; i++) {
            if (degree[i] < 2) continue;
            int tmp_a = degree[i] - 2;
            if (tmp_a >= ans) continue;
            for (int j = i + 1; j <= n; j++) {
                if (degree[j] < 2) continue;
                if (graph[i][j] == false) continue;
                int tmp_b = tmp_a + degree[j] - 2;
                if (tmp_b >= ans) continue;
                for (int k = j + 1; k <= n; k++) {
                    if (degree[k] < 2) continue;
                    if (graph[j][k] == false || graph[i][k] == false) {
                        continue;
                    }
                    ans = min(ans, tmp_b + degree[k] - 2);
                }
            }
        }
        
        return ans == INT_MAX? -1 : ans;
    }
};

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