Create union_find.cpp

Author: wisdompeak

Template/Union_Find/union_find.cpp

@@ -0,0 +1,23 @@
+struct DSU {
+    vector<int> p, r;
+    DSU(int n): p(n,-1), r(n,0) {
+        iota(p.begin(), p.end(), 0);
+    }
+    int find(int x) {
+        return p[x]==x ? x : p[x]=find(p[x]);
+    }
+    bool unite(int a, int b) {
+        a = find(a); b = find(b);
+        if (a == b) return false;
+        if (r[a] < r[b]) swap(a,b);
+        p[b] = a;
+        if (r[a]==r[b]) ++r[a];
+        return true;
+    }
+};
+
+int main {
+  DSU dsu(n);
+  dsu.unite(u,v);
+  if (dsu.find(u)==dsu.find(v) {}
+}