0018-4Sum.go

funcfourSum(nums []int, targetint) [][]int {
iflen(nums) <4 {
return [][]int{}
 }

sort.Ints(nums)

result:=make([][]int, 0)

fori, ival:=rangenums {
ifi!=0&&nums[i] ==nums[i-1] {
continue
 }

forj:=i+1; j<len(nums) -1; j++ {
ifj!=i+1&&nums[j] ==nums[j-1] {
continue
 }

jval:=nums[j]

forl, r:=j+1, len(nums) -1; l<r; {
lval, rval:=nums[l], nums[r]

sum:=ival+jval+lval+rval
switch {
casesum<target:
l++
casesum>target:
r--
default:
result=append(result, []int{ival, jval, lval, rval})
for ; l<r&&nums[l] ==nums[l+1]; l++ {
 }
for ; l<r&&nums[r] ==nums[r-1]; r-- {
 }
l++
r--
 }
 }
 }
 }

returnresult
}