day19, struggling part2, not quite yet

day19/intervals.go

@@ -0,0 +1,57 @@
+package day19
+
+import (
+	"sort"
+)
+
+func merge(intervals [][]int) [][]int {
+    const start, end = 0, 1
+
+    var merged [][]int
+
+    if len(intervals) > 1 {
+        sort.Slice(intervals, func(i, j int) bool {
+            return intervals[i][start] < intervals[j][start]
+        })
+    }
+
+    for _, interval := range intervals {
+        last := len(merged) - 1
+        if last < 0 || interval[start] > merged[last][end] {
+            merged = append(merged,
+                []int{start: interval[start], end: interval[end]},
+            )
+        } else if interval[end] > merged[last][end] {
+            merged[last][end] = interval[end]
+        }
+    }
+
+    return merged[:len(merged):len(merged)]
+}
+
+func applyLessThan(intervals [][]int, n int) [][]int {
+	var lessers [][]int
+	for _, interval := range intervals {
+		from := interval[0]
+		if from >= n {
+			continue
+		}
+		lessers = append(lessers, []int{from, n-1})
+	}
+
+	return lessers
+}
+
+func applyMoreThan(intervals [][]int, n int) [][]int {
+	var greaters [][]int
+	for _, interval := range intervals {
+		to := interval[1]
+		if to <= n {
+			continue
+		}
+		greaters = append(greaters, []int{n+1, to})
+	}
+	// log.Printf(">>>> in applyMoreThan %d to %+v ; result %+v", n, intervals, greaters)
+
+	return greaters
+}