0210-course-schedule-ii.go

constCRS=0
constPRE=1
funcfindOrder(numCoursesint, prerequisites [][]int) []int {
prereq:=make([][]int, 0)
fori:=0; i<numCourses; i++ {
prereq=append(prereq, make([]int, 0))
 }
for_, edge:=rangeprerequisites {
prereq[edge[CRS]] =append(prereq[edge[CRS]], edge[PRE])
 }

output:=make([]int, 0)
visit, cycle:=make([]bool, numCourses), make([]bool, numCourses)

vardfsfunc(int) bool
dfs=func(crsint) bool {
ifcycle[crs] {
returnfalse
 } elseifvisit[crs] {
returntrue
 }

cycle[crs] =true
for_, pre:=rangeprereq[crs] {
if!dfs(pre) {
returnfalse
 }
 }
cycle[crs] =false
visit[crs] =true
output=append(output, crs)
returntrue
 }

forc:=0; c<numCourses; c++ {
ifdfs(c) ==false {
return []int{}
 }
 }
returnoutput
}