{ "data": { "question": { "questionId": "2671", "questionFrontendId": "2608", "categoryTitle": "Algorithms", "boundTopicId": 2200594, "title": "Shortest Cycle in a Graph", "titleSlug": "shortest-cycle-in-a-graph", "content": "
There is a bi-directional graph with n
vertices, where each vertex is labeled from 0
to n - 1
. The edges in the graph are represented by a given 2D integer array edges
, where edges[i] = [ui, vi]
denotes an edge between vertex ui
and vertex vi
. Every vertex pair is connected by at most one edge, and no vertex has an edge to itself.
Return the length of the shortest cycle in the graph. If no cycle exists, return -1
.
A cycle is a path that starts and ends at the same node, and each edge in the path is used only once.
\n\n\n
Example 1:
\n\n\nInput: n = 7, edges = [[0,1],[1,2],[2,0],[3,4],[4,5],[5,6],[6,3]]\nOutput: 3\nExplanation: The cycle with the smallest length is : 0 -> 1 -> 2 -> 0 \n\n\n
Example 2:
\n\n\nInput: n = 4, edges = [[0,1],[0,2]]\nOutput: -1\nExplanation: There are no cycles in this graph.\n\n\n
\n
Constraints:
\n\n2 <= n <= 1000
1 <= edges.length <= 1000
edges[i].length == 2
0 <= ui, vi < n
ui != vi
现有一个含 n
个顶点的 双向 图,每个顶点按从 0
到 n - 1
标记。图中的边由二维整数数组 edges
表示,其中 edges[i] = [ui, vi]
表示顶点 ui
和 vi
之间存在一条边。每对顶点最多通过一条边连接,并且不存在与自身相连的顶点。
返回图中 最短 环的长度。如果不存在环,则返回 -1
。
环 是指以同一节点开始和结束,并且路径中的每条边仅使用一次。
\n\n\n\n
示例 1:
\n\n输入:n = 7, edges = [[0,1],[1,2],[2,0],[3,4],[4,5],[5,6],[6,3]]\n输出:3\n解释:长度最小的循环是:0 -> 1 -> 2 -> 0 \n\n\n
示例 2:
\n\n输入:n = 4, edges = [[0,1],[0,2]]\n输出:-1\n解释:图中不存在循环\n\n\n
\n\n
提示:
\n\n2 <= n <= 1000
1 <= edges.length <= 1000
edges[i].length == 2
0 <= ui, vi < n
ui != vi
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