^^

day-5/two.go

@@ -16,8 +16,9 @@ type bound struct {
 }
 
 // newBound returns a bound type
+// it defines an open ended interval
 func newBound(lower, upper int) bound {
-	return bound{lower: lower, upper: upper}
+	return bound{lower: lower, upper: upper - 1}
 }
 
 // nextTransform recursively calculates each new set of seed ranges for each set of data in dataMap
@@ -42,10 +43,10 @@ func nextTransform(i int, in []bound) []bound {
 
 					// append unmatched portions of seed range back into queue
 					if start > r.lower {
-						q.enqueue(newBound(r.lower, start-1))
+						q.enqueue(newBound(r.lower, start))
 					}
 					if r.upper > end {
-						q.enqueue(newBound(end, r.upper-1))
+						q.enqueue(newBound(end, r.upper))
 					}
 					return true
 				}
@@ -70,7 +71,7 @@ func two(lines []string) int {
 		go func(i int) {
 			defer wg.Done()
 			mu.Lock()
-			seedRanges = append(seedRanges, nextTransform(0, []bound{newBound(seeds[i], seeds[i]+seeds[i+1]-1)})...)
+			seedRanges = append(seedRanges, nextTransform(0, []bound{newBound(seeds[i], seeds[i]+seeds[i+1])})...)
 			mu.Unlock()
 		}(i)
 	}