454. 四数相加 II #
题目地址 #
解题思路 #
具体实现 #
```go
package main
import "fmt"
func fourSumCount(nums1 []int, nums2 []int, nums3 []int, nums4 []int) int {
count := 0
m := make(map[int]int)
for _, a := range nums1 {
for _, b := range nums2 {
m[a+b]++
}
}
for _, c := range nums3 {
for _, d := range nums4 {
target := 0 - (c + d)
if v, ok := m[target]; ok {
count += v
}
}
}
return count
}
func main() {
nums1 := []int{1, 2}
nums2 := []int{-2, -1}
nums3 := []int{-1, 2}
nums4 := []int{0, 2}
ret := fourSumCount(nums1, nums2, nums3, nums4)
fmt.Println(ret)
}
```