course_schedule.go

package main




funccanFinish(numCoursesint, prerequisites [][]int) bool {
graph:=make([][]int, numCourses)
fori:=0; i<numCourses; i++ {
graph[i] =make([]int, 0)
 }

for_, pre:=rangeprerequisites {
x:=pre[0]
y:=pre[1]
graph[x] =append(graph[x], y)
 }

visited:=make([]int, numCourses)
fori:=0; i<numCourses; i++ {
ifhasCycle(graph, visited, i) {
returnfalse// Cycle detected
 }
 }

returntrue
}

funchasCycle(graph [][]int, visited []int, nodeint) bool {
ifvisited[node] ==1 {
returntrue// Cycle detected
 }
ifvisited[node] ==-1 {
returnfalse// Already visited and no cycle
 }

visited[node] =1// Mark node as visited

for_, neighbor:=rangegraph[node] {
ifhasCycle(graph, visited, neighbor) {
returntrue// Cycle detected
 }
 }

visited[node] =-1// Mark node as visited and no cycle
returnfalse
}