35 lines
668 B
Go
35 lines
668 B
Go
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package main
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func getAncestors(n int, edges [][]int) [][]int {
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fromEdges := func() [][]int {
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neighbours := make([][]int, n)
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for _, edge := range edges {
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u, v := edge[0], edge[1]
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neighbours[u] = append(neighbours[u], v)
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}
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return neighbours
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}
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neighbours := fromEdges()
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ancestors := make([][]int, n)
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var dfs func(int, int)
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dfs = func(ancestor, node int) {
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for _, next := range neighbours[node] {
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vertices := ancestors[next]
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if len(vertices) == 0 || vertices[len(vertices)-1] != ancestor {
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ancestors[next] = append(ancestors[next], ancestor)
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dfs(ancestor, next)
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}
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}
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}
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for i := range n {
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dfs(i, i)
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}
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return ancestors
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}
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