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Merge pull request #526 from vaskoz/day255
Day255
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Original file line number | Diff line number | Diff line change |
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package day255 | ||
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// Graph is an integer based ajacency matrix. | ||
type Graph map[int][]int | ||
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// TransitiveClosure returns the transitive closure | ||
// matrix. | ||
func TransitiveClosure(g Graph) [][]int { | ||
var largest int | ||
for start, ends := range g { | ||
if start > largest { | ||
largest = start | ||
} | ||
for _, node := range ends { | ||
if node > largest { | ||
largest = node | ||
} | ||
} | ||
} | ||
result := make([][]int, largest+1) | ||
for i := range result { | ||
result[i] = make([]int, largest+1) | ||
} | ||
visited := make(map[int]struct{}, largest+1) | ||
result = transitiveClosure(-1, g, result, visited) | ||
return result | ||
} | ||
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func transitiveClosure(node int, g Graph, result [][]int, visited map[int]struct{}) [][]int { | ||
if node == -1 { | ||
for start := range g { | ||
result = transitiveClosure(start, g, result, visited) | ||
} | ||
} else { | ||
for start := range visited { | ||
result[start][node] = 1 | ||
} | ||
visited[node] = struct{}{} | ||
for _, n := range g[node] { | ||
if n == node { | ||
result[node][n] = 1 | ||
} else if _, found := visited[n]; !found { | ||
result = transitiveClosure(n, g, result, visited) | ||
} | ||
} | ||
delete(visited, node) | ||
} | ||
return result | ||
} |
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Original file line number | Diff line number | Diff line change |
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package day255 | ||
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import ( | ||
"reflect" | ||
"testing" | ||
) | ||
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// nolint | ||
var testcases = []struct { | ||
g Graph | ||
expected [][]int | ||
}{ | ||
{ | ||
Graph{ | ||
0: {0, 1, 3}, | ||
1: {1, 2}, | ||
2: {2}, | ||
3: {3}, | ||
}, | ||
[][]int{ | ||
{1, 1, 1, 1}, | ||
{0, 1, 1, 0}, | ||
{0, 0, 1, 0}, | ||
{0, 0, 0, 1}, | ||
}, | ||
}, | ||
{ | ||
Graph{ | ||
0: {1, 3}, | ||
1: {2}, | ||
2: {}, | ||
3: {}, | ||
}, | ||
[][]int{ | ||
{0, 1, 1, 1}, | ||
{0, 0, 1, 0}, | ||
{0, 0, 0, 0}, | ||
{0, 0, 0, 0}, | ||
}, | ||
}, | ||
{ | ||
Graph{ | ||
0: {1, 3}, | ||
1: {2}, | ||
2: {3}, | ||
3: {2}, | ||
}, | ||
[][]int{ | ||
{0, 1, 1, 1}, | ||
{0, 0, 1, 1}, | ||
{0, 0, 0, 1}, | ||
{0, 0, 1, 0}, | ||
}, | ||
}, | ||
} | ||
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func TestTransitiveClosure(t *testing.T) { | ||
t.Parallel() | ||
for _, tc := range testcases { | ||
if result := TransitiveClosure(tc.g); !reflect.DeepEqual(result, tc.expected) { | ||
t.Errorf("Expected %v, got %v", tc.expected, result) | ||
} | ||
} | ||
} | ||
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func BenchmarkTransitiveClosure(b *testing.B) { | ||
for i := 0; i < b.N; i++ { | ||
for _, tc := range testcases { | ||
TransitiveClosure(tc.g) | ||
} | ||
} | ||
} |