添加 structures

structures/PriorityQueue_test.go

@@ -0,0 +1,53 @@
+package structures
+
+import (
+	"container/heap"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_priorityQueue(t *testing.T) {
+	ast := assert.New(t)
+
+	// Some items and their priorities.
+	items := map[string]int{
+		"banana": 2, "apple": 1, "pear": 3,
+	}
+
+	// Create a priority queue, put the items in it, and
+	// establish the priority queue (heap) invariants.
+	pq := make(PQ, len(items))
+	i := 0
+	for value, priority := range items {
+		pq[i] = &entry{
+			key:      value,
+			priority: priority,
+			index:    i,
+		}
+		i++
+	}
+	heap.Init(&pq)
+
+	// Insert a new item and then modify its priority.
+	it := &entry{
+		key:      "orange",
+		priority: 5,
+	}
+	heap.Push(&pq, it)
+	pq.update(it, it.key, 0)
+
+	// Some items and their priorities.
+	expected := []string{
+		"orange",
+		"apple",
+		"banana",
+		"pear",
+	}
+
+	// Take the items out; they arrive in decreasing priority order.
+	for pq.Len() > 0 {
+		it := heap.Pop(&pq).(*entry)
+		ast.Equal(expected[it.priority], it.key)
+	}
+}