37 lines
906 B
Java
37 lines
906 B
Java
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import java.util.*;
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import java.util.stream.Stream;
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// https://en.wikipedia.org/wiki/Topological_sorting
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public class TopologicalSort {
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static void dfs(List<Integer>[] graph, boolean[] used, List<Integer> order, int u) {
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used[u] = true;
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for (int v : graph[u])
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if (!used[v])
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dfs(graph, used, order, v);
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order.add(u);
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}
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public static List<Integer> topologicalSort(List<Integer>[] graph) {
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int n = graph.length;
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boolean[] used = new boolean[n];
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List<Integer> order = new ArrayList<>();
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for (int i = 0; i < n; i++)
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if (!used[i])
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dfs(graph, used, order, i);
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Collections.reverse(order);
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return order;
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}
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// Usage example
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public static void main(String[] args) {
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List<Integer>[] g = Stream.generate(ArrayList::new).limit(3).toArray(List[]::new);
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g[2].add(0);
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g[2].add(1);
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g[0].add(1);
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List<Integer> order = topologicalSort(g);
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System.out.println(order);
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}
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}
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