add new solutions

solutions/12/q1226/solution.go

@@ -1,20 +1,39 @@
 package q1226
 
-func abs(i int) int {
-	if i < 0 {
-		return -i
-	}
-	return i
+import "sync"
+
+var (
+	pick  = sync.Mutex{}
+	forks = [5]sync.Mutex{}
+)
+
+type DiningPhilosophers struct {
 }
 
-func minTimeToVisitAllPoints(points [][]int) int {
-	time := 0
-	for i := 0; i < len(points)-1; i++ {
-		cur, next := points[i], points[i+1]
-		dx, dy := abs(cur[0]-next[0]), abs(cur[1]-next[1])
-		time += max(dx, dy)
-	}
-	return time
+func (p *DiningPhilosophers) wantsToEat(
+	philosopher int,
+	pickLeftFork func(),
+	pickRightFork func(),
+	eat func(),
+	putLeftFork func(),
+	putRightFork func(),
+) {
+	l, r := &forks[philosopher], &forks[(philosopher+1)%5]
+
+	pick.Lock()
+	l.Lock()
+	r.Lock()
+	pick.Unlock()
+
+	pickLeftFork()
+	pickRightFork()
+	eat()
+
+	putLeftFork()
+	l.Unlock()
+	putRightFork()
+	r.Unlock()
 }
 
-var _ = minTimeToVisitAllPoints
+var _t = DiningPhilosophers{}
+var _ = _t.wantsToEat