add new solutions

solutions/8/q841/solution.go

@@ -0,0 +1,23 @@
+package q841
+
+func canVisitAllRooms(rooms [][]int) bool {
+	locked := len(rooms) - 1
+
+	opened := make([]bool, len(rooms))
+	opened[0] = true
+
+	queue := []int{0}
+	for ; len(queue) > 0; queue = queue[1:] {
+		for _, i := range rooms[queue[0]] {
+			if opened[i] {
+				continue
+			}
+			opened[i] = true
+			locked--
+			queue = append(queue, i)
+		}
+	}
+	return locked == 0
+}
+
+var _ = canVisitAllRooms

solutions/8/q875/solution.go

@@ -0,0 +1,31 @@
+package q875
+
+import (
+	"math"
+	"slices"
+)
+
+func canEat(piles []int, h, speed int) bool {
+	needed := 0
+	for _, n := range piles {
+		needed += int(math.Ceil(float64(n) / float64(speed)))
+	}
+	return needed <= h
+}
+
+func minEatingSpeed(piles []int, h int) int {
+	maxK := slices.Max(piles)
+
+	l, r := 1, maxK+1
+	for l < r {
+		m := (l + r) / 2
+		if canEat(piles, h, m) {
+			r = m
+		} else {
+			l = m + 1
+		}
+	}
+	return l
+}
+
+var _ = minEatingSpeed