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花花酱 LeetCode 886. Possible Bipartition


Given a set of N people (numbered 1, 2, ..., N), we would like to split everyone into two groups of any size.

Each person may dislike some other people, and they should not go into the same group.

Formally, if dislikes[i] = [a, b], it means it is not allowed to put the people numbered a and b into the same group.

Return true if and only if it is possible to split everyone into two groups in this way.

Example 1:

Input: N = 4, dislikes = [[1,2],[1,3],[2,4]]
Output: true
Explanation: group1 [1,4], group2 [2,3]

Example 2:

Input: N = 3, dislikes = [[1,2],[1,3],[2,3]]
Output: false

Example 3:

Input: N = 5, dislikes = [[1,2],[2,3],[3,4],[4,5],[1,5]]
Output: false


  1. 1 <= N <= 2000
  2. 0 <= dislikes.length <= 10000
  3. 1 <= dislikes[i][j] <= N
  4. dislikes[i][0] < dislikes[i][1]
  5. There does not exist i != j for which dislikes[i] == dislikes[j].


Solution: Graph Coloring

Color a node with one color, and color all it’s disliked nodes with another color, if can not finish return false.

Time complexity: O(V+E)

Space complexity: O(V+E)

C++ / DFS

C++ / BFS

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