Vector and Priority queue assert

pkg/hnsw/pq_test.go

@@ -0,0 +1,105 @@
+package hnsw
+
+import (
+	"testing"
+)
+
+func TestPQ(t *testing.T) {
+
+	t.Run("bricks and ladders || min heap", func(t *testing.T) {
+		type Case struct {
+			heights  []int
+			bricks   int
+			ladders  int
+			expected int
+		}
+
+		cases := [3]Case{
+			{
+				heights:  []int{4, 2, 7, 6, 9, 14, 12},
+				bricks:   5,
+				ladders:  1,
+				expected: 4,
+			},
+			{
+				heights:  []int{4, 12, 2, 7, 3, 18, 20, 3, 19},
+				bricks:   10,
+				ladders:  2,
+				expected: 7,
+			},
+			{
+				heights:  []int{14, 3, 19, 3},
+				bricks:   17,
+				ladders:  0,
+				expected: 3,
+			},
+		}
+
+		for _, c := range cases {
+			res, err := furthestBuildings(c.heights, c.bricks, c.ladders)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if res != c.expected {
+				t.Errorf("got %d, want %d", res, c.expected)
+			}
+		}
+
+	})
+}
+
+func furthestBuildings(heights []int, bricks, ladders int) (int, error) {
+
+	ladderJumps := NewBaseQueue(MinComparator{})
+
+	for idx := 0; idx < len(heights)-1; idx++ {
+		height := heights[idx]
+		nextHeight := heights[idx+1]
+
+		if height >= nextHeight {
+			continue
+		}
+
+		jump := nextHeight - height
+
+		ladderJumps.Insert(Id(idx), float32(jump))
+
+		if ladderJumps.Len() > ladders {
+			minLadderJump, err := ladderJumps.Peel()
+			if err != nil {
+				return -1, err
+			}
+
+			if bricks-int(minLadderJump.dist) < 0 {
+				return idx, nil
+			}
+
+			bricks -= int(minLadderJump.dist)
+		}
+	}
+
+	return len(heights) - 1, nil
+}
+
+/*
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+ */