Refactor prio queue

Author: korthaj

mst.go

@@ -22,7 +22,7 @@ func MST(g Iterator) (parent []int) {
 	}
 
 	// Prim's algorithm
-	Q := newMstQueue(cost)
+	Q := newQueue(cost)
 	for Q.Len() > 0 {
 		v := heap.Pop(Q).(int)
 		g.Visit(v, func(w int, c int64) (skip bool) {
@@ -36,53 +36,3 @@ func MST(g Iterator) (parent []int) {
 	}
 	return
 }
-
-type mstQueue struct {
-	heap  []int // vertices in heap order
-	index []int // index of each vertex in the heap
-	cost  []int64
-}
-
-func newMstQueue(cost []int64) *mstQueue {
-	n := len(cost)
-	h := &mstQueue{
-		heap:  make([]int, n),
-		index: make([]int, n),
-		cost:  cost,
-	}
-	for i := range h.heap {
-		h.heap[i] = i
-		h.index[i] = i
-	}
-	return h
-}
-
-func (m *mstQueue) Len() int { return len(m.heap) }
-
-func (m *mstQueue) Less(i, j int) bool {
-	return m.cost[m.heap[i]] < m.cost[m.heap[j]]
-}
-
-func (m *mstQueue) Swap(i, j int) {
-	m.heap[i], m.heap[j] = m.heap[j], m.heap[i]
-	m.index[m.heap[i]] = i
-	m.index[m.heap[j]] = j
-}
-
-func (m *mstQueue) Push(x interface{}) {} // Not used
-
-func (m *mstQueue) Pop() interface{} {
-	n := len(m.heap) - 1
-	v := m.heap[n]
-	m.index[v] = -1
-	m.heap = m.heap[:n]
-	return v
-}
-
-func (m *mstQueue) Update(v int) {
-	heap.Fix(m, m.index[v])
-}
-
-func (m *mstQueue) Contains(v int) bool {
-	return m.index[v] >= 0
-}

path.go

@@ -44,7 +44,7 @@ func ShortestPaths(g Iterator, v int) (parent []int, dist []int64) {
 	dist[v] = 0
 
 	// Dijkstra's algorithm
-	Q := emptySpQueue(dist)
+	Q := emptyQueue(dist)
 	heap.Push(Q, v)
 	for Q.Len() > 0 {
 		v = heap.Pop(Q).(int)
@@ -66,43 +66,3 @@ func ShortestPaths(g Iterator, v int) (parent []int, dist []int64) {
 	}
 	return
 }
-
-type spQueue struct {
-	heap  []int // vertices in heap order
-	index []int // index of each vertex in the heap
-	dist  []int64
-}
-
-func emptySpQueue(dist []int64) *spQueue {
-	return &spQueue{dist: dist, index: make([]int, len(dist))}
-}
-
-func (pq *spQueue) Len() int { return len(pq.heap) }
-
-func (pq *spQueue) Less(i, j int) bool {
-	return pq.dist[pq.heap[i]] < pq.dist[pq.heap[j]]
-}
-
-func (pq *spQueue) Swap(i, j int) {
-	pq.heap[i], pq.heap[j] = pq.heap[j], pq.heap[i]
-	pq.index[pq.heap[i]] = i
-	pq.index[pq.heap[j]] = j
-}
-
-func (pq *spQueue) Push(x interface{}) {
-	n := len(pq.heap)
-	v := x.(int)
-	pq.heap = append(pq.heap, v)
-	pq.index[v] = n
-}
-
-func (pq *spQueue) Pop() interface{} {
-	n := len(pq.heap) - 1
-	v := pq.heap[n]
-	pq.heap = pq.heap[:n]
-	return v
-}
-
-func (pq *spQueue) Update(v int) {
-	heap.Fix(pq, pq.index[v])
-}