使用O(n 4)时间计算有向图的传递闭包的算法。

for an assignment I am asked by to find find an algorithm that calculates the transitive closure of a directed graph using O(n 4 ) time. We already learned about the floyd warshall algorithm, which is a lot better, so can someone help me create one that runs in O(n4) time? is there such an algorithm? for an assignment I am asked by to find find an