规范格式

leetcode/0923.3Sum-With-Multiplicity/923. 3Sum With Multiplicity.go

@@ -0,0 +1,41 @@
+package leetcode
+
+import (
+	"sort"
+)
+
+func threeSumMulti(A []int, target int) int {
+	mod := 1000000007
+	counter := map[int]int{}
+	for _, value := range A {
+		counter[value]++
+	}
+
+	uniqNums := []int{}
+	for key := range counter {
+		uniqNums = append(uniqNums, key)
+	}
+	sort.Ints(uniqNums)
+
+	res := 0
+	for i := 0; i < len(uniqNums); i++ {
+		ni := counter[uniqNums[i]]
+		if (uniqNums[i]*3 == target) && counter[uniqNums[i]] >= 3 {
+			res += ni * (ni - 1) * (ni - 2) / 6
+		}
+		for j := i + 1; j < len(uniqNums); j++ {
+			nj := counter[uniqNums[j]]
+			if (uniqNums[i]*2+uniqNums[j] == target) && counter[uniqNums[i]] > 1 {
+				res += ni * (ni - 1) / 2 * nj
+			}
+			if (uniqNums[j]*2+uniqNums[i] == target) && counter[uniqNums[j]] > 1 {
+				res += nj * (nj - 1) / 2 * ni
+			}
+			c := target - uniqNums[i] - uniqNums[j]
+			if c > uniqNums[j] && counter[c] > 0 {
+				res += ni * nj * counter[c]
+			}
+		}
+	}
+	return res % mod
+}