go: add «2406. Divide Intervals Into Minimum Number of Groups»

URL:	https://leetcode.com/problems/divide-intervals-into-minimum-number-of-groups/
Signed-off-by: Matej Focko <me@mfocko.xyz>

go/divide-intervals-into-minimum-number-of-groups.go

@@ -0,0 +1,27 @@
+package main
+
+func minGroups(intervals [][]int) int {
+	minStart, maxEnd := intervals[0][0], intervals[0][1]
+	for _, interval := range intervals {
+		start, end := interval[0], interval[1]
+
+		minStart = min(minStart, start)
+		maxEnd = max(maxEnd, end)
+	}
+
+	hits := make([]int, maxEnd+2)
+	for _, interval := range intervals {
+		start, end := interval[0], interval[1]
+		hits[start]++
+		hits[end+1]--
+	}
+
+	concurrent, maxConcurrent := 0, 0
+	for i := minStart; i <= maxEnd; i++ {
+		concurrent += hits[i]
+
+		maxConcurrent = max(maxConcurrent, concurrent)
+	}
+
+	return maxConcurrent
+}