diff --git a/leetcode/1791.Find-Center-of-Star-Graph/README.md b/leetcode/1791.Find-Center-of-Star-Graph/README.md new file mode 100644 index 00000000..88c90365 --- /dev/null +++ b/leetcode/1791.Find-Center-of-Star-Graph/README.md @@ -0,0 +1,52 @@ +# [1791.Find Center of Star Graph](https://leetcode-cn.com/problems/find-center-of-star-graph/) + +## 题目 + +There is an undirected star graph consisting of n nodes labeled from 1 to n. A star graph is a graph where there is one center node and exactly n - 1 edges that connect the center node with every other node. + +You are given a 2D integer array edges where each edges[i] = [ui, vi] indicates that there is an edge between the nodes ui and vi. Return the center of the given star graph. + +**Example 1:** + +![https://assets.leetcode.com/uploads/2021/02/24/star_graph.png:w](https://assets.leetcode.com/uploads/2021/02/24/star_graph.png) + + Input: edges = [[1,2],[2,3],[4,2]] + Output: 2 + Explanation: As shown in the figure above, node 2 is connected to every other node, so 2 is the center. + +**Example 2:** + + Input: edges = [[1,2],[5,1],[1,3],[1,4]] + Output: 1 + +**Constraints:** + +- 3 <= n <= 100000 +- edges.length == n - 1 +- edges[i].length == 2 +- 1 <= ui, vi <= n +- ui != vi +- The given edges represent a valid star graph. + +## 题目大意 + +有一个无向的 星型 图,由 n 个编号从 1 到 n 的节点组成。星型图有一个 中心 节点,并且恰有 n - 1 条边将中心节点与其他每个节点连接起来。 + +给你一个二维整数数组 edges ,其中 edges[i] = [ui, vi] 表示在节点 ui 和 vi 之间存在一条边。请你找出并返回 edges 所表示星型图的中心节点。 + +## 解题思路 + +- 求出edges中前两个元素的共同值,即是中心节点 + +## 代码 + +```go +package leetcode + +func findCenter(edges [][]int) int { + if edges[0][0] == edges[1][0] || edges[0][0] == edges[1][1] { + return edges[0][0] + } + return edges[0][1] +} +```