add new solutions

solutions/13/q1365/solution.go

@@ -0,0 +1,27 @@
+package q1365
+
+import "slices"
+
+func smallerNumbersThanCurrent(nums []int) []int {
+	buf := make([]int, 2*len(nums))
+
+	positions := buf[0:len(nums)]
+	for i := range positions {
+		positions[i] = i
+	}
+	slices.SortFunc(positions, func(a, b int) int { return nums[a] - nums[b] })
+
+	nLesser := buf[len(nums):]
+	last := -1
+	for i, p := range positions {
+		if nums[p] == last {
+			nLesser[p] = nLesser[positions[i-1]]
+		} else {
+			last = nums[p]
+			nLesser[p] = i
+		}
+	}
+	return nLesser
+}
+
+var _ = smallerNumbersThanCurrent