60 lines
1.1 KiB
Go
60 lines
1.1 KiB
Go
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package main
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import (
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"cmp"
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pq "github.com/emirpasic/gods/v2/queues/priorityqueue"
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)
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func maxProbability(n int, edges [][]int, succProb []float64, start int, end int) float64 {
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type Edge struct {
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v int
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p float64
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}
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makeGraph := func() [][]Edge {
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g := make([][]Edge, n)
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for i, edge := range edges {
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u, v, p := edge[0], edge[1], succProb[i]
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g[u] = append(g[u], Edge{v: v, p: p})
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g[v] = append(g[v], Edge{v: u, p: p})
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}
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return g
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}
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g := makeGraph()
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type Entry struct {
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probability float64
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u int
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}
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byProbability := func(a, b Entry) int {
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return -cmp.Compare(a.probability, b.probability)
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}
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maxP := make([]float64, n)
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q := pq.NewWith(byProbability)
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maxP[start] = 1
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q.Enqueue(Entry{probability: maxP[start], u: start})
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for candidate, ok := q.Dequeue(); ok; candidate, ok = q.Dequeue() {
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if candidate.u == end {
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return candidate.probability
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}
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for _, edge := range g[candidate.u] {
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p := candidate.probability * edge.p
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if p > maxP[edge.v] {
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maxP[edge.v] = p
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q.Enqueue(Entry{probability: p, u: edge.v})
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}
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}
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}
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return 0
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}
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