34 lines
789 B
Java
34 lines
789 B
Java
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// https://en.wikipedia.org/wiki/Disjoint-set_data_structure with path compression heuristic
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// Complexity of operations is O(log(n)) on average
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public class DisjointSets {
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public static int[] createSets(int size) {
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int[] p = new int[size];
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for (int i = 0; i < size; i++)
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p[i] = i;
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return p;
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}
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public static int root(int[] p, int x) {
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return x == p[x] ? x : (p[x] = root(p, p[x]));
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}
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public static boolean unite(int[] p, int a, int b) {
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a = root(p, a);
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b = root(p, b);
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if (a != b) {
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p[a] = b;
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return true;
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}
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return false;
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}
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// Usage example
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public static void main(String[] args) {
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int[] p = createSets(10);
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System.out.println(false == (root(p, 0) == root(p, 9)));
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unite(p, 0, 9);
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System.out.println(true == (root(p, 0) == root(p, 9)));
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}
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}
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