版权声明:原创勿转 https://cloud.tencent.com/developer/article/1412980
和两个数相加的题目比较类似的解法
func fourSumCount(A []int, B []int, C []int, D []int) int {
maps := make(map[int]int)
for i := 0; i < len(A); i++ {
for j := 0; j < len(B); j++ {
maps[A[i]+B[j]]++
}
}
ret := 0
for i := 0; i < len(C); i++ {
for j := 0; j < len(D); j++ {
ret += maps[-1*(C[i]+D[j])]
}
}
return ret
}