diff --git a/algorithm/breadth_first_search.h b/algorithm/breadth_first_search.h
index de71d0e..6309283 100644
--- a/algorithm/breadth_first_search.h
+++ b/algorithm/breadth_first_search.h
@@ -14,24 +14,24 @@ class BreadthFirstSearch {
 public:
   BreadthFirstSearch() = default;
 
-  BreadthFirstSearch(std::map<T, std::set<T>> adjList)
+  BreadthFirstSearch(std::unordered_map<T, std::unordered_set<T>> adjList)
     : adjList(adjList) {}
 
   // Traverse whole graph using the BFS search, and save the tree graph
   // which is created when visiting new vertices (Breadth First Tree)
-  std::map<T, std::set<T>> execute(const T& root);
+  std::unordered_map<T, std::unordered_set<T>> execute(const T& root);
 
   // Search if target vertex exists in graph
   bool query(const T& root, const T& target);
 private:
   // Represents the graph on which the algorithm will be executed
-  std::map<T, std::set<T>> adjList;
+  std::unordered_map<T, std::unordered_set<T>> adjList;
 }; 
 
 template<typename T>
-std::map<T, std::set<T>> BreadthFirstSearch<T>::execute(const T& root) {
-  std::map<T, std::set<T>> tree;
-  std::map<T, bool> visited;
+std::unordered_map<T, std::unordered_set<T>> BreadthFirstSearch<T>::execute(const T& root) {
+  std::unordered_map<T, std::unordered_set<T>> tree;
+  std::unordered_map<T, bool> visited;
   std::queue<T> Q;
   Q.push(root);
   visited[root] = true;
@@ -54,7 +54,7 @@ std::map<T, std::set<T>> BreadthFirstSearch<T>::execute(const T& root) {
 
 template<typename T>
 bool BreadthFirstSearch<T>::query(const T& root, const T& target) {
-  std::map<T, bool> visited;
+  std::unordered_map<T, bool> visited;
   std::queue<T> Q;
   Q.push(root);
   visited[root] = true;
diff --git a/algorithm/frigioni.h b/algorithm/frigioni.h
index 86e3bc5..fdd0e44 100644
--- a/algorithm/frigioni.h
+++ b/algorithm/frigioni.h
@@ -31,10 +31,10 @@ public:
   void remove(const std::vector<std::pair<T, T>>& edges);
 private:
   // Transitive closure matrix, used to answer reachability queries in O(1)
-  std::map<T, std::map<T, bool>> TC;
+  std::unordered_map<T, std::unordered_map<T, bool>> TC;
 
   // For each SCC, store a reachability tree created as a BFS tree
-  std::map<T, BreadthFirstTree<T>> RT;
+  std::unordered_map<T, BreadthFirstTree<T>> RT;
 
   // For each SCC, store collections of incoming, outgoing and internal edges
   struct Edges {
@@ -42,7 +42,7 @@ private:
     std::set<std::pair<T, T>> inc;
     std::set<std::pair<T, T>> out;
   };
-  std::map<T, Edges> E;
+  std::unordered_map<T, Edges> E;
   
   // Decremental maintenance of strongly connected components
   RodittyZwick<T> rodittyZwick;
@@ -101,7 +101,7 @@ void Frigioni<T>::remove(const std::vector<std::pair<T, T>>& edges) {
       Eext.push_back({ u, v });
   }
 
-  std::map<T, std::stack<T>> H;
+  std::unordered_map<T, std::stack<T>> H;
   for (const auto& [u, v] : Eint) {
     this->G.remove(u, v);
     rodittyZwick.remove(u, v);
diff --git a/algorithm/henzinger_king.h b/algorithm/henzinger_king.h
index c2c8603..aa9516e 100644
--- a/algorithm/henzinger_king.h
+++ b/algorithm/henzinger_king.h
@@ -47,8 +47,8 @@ private:
   std::set<T> S;
 
   // Maintain in-out bfs trees
-  std::map<T, BreadthFirstTree<T>> In;
-  std::map<T, BreadthFirstTree<T>> Out;
+  std::unordered_map<T, BreadthFirstTree<T>> In;
+  std::unordered_map<T, BreadthFirstTree<T>> Out;
 };
 
 template<typename T>
diff --git a/algorithm/italiano.h b/algorithm/italiano.h
index 0eb4917..ab1b40b 100644
--- a/algorithm/italiano.h
+++ b/algorithm/italiano.h
@@ -28,20 +28,20 @@ public:
   void remove(const T& u, const T& v) override;
 private:
   // Transitive closure matrix
-  std::map<T, std::map<T, bool>> TC;
-
+  std::unordered_map<T, std::unordered_map<T, bool>> TC;
+  
   // For each vertex, store a reachability tree created as a BFS tree
-  std::map<T, BreadthFirstTree<T>> RT;
+  std::unordered_map<T, BreadthFirstTree<T>> RT;
 
   // For each vertex, store collections of its incoming and outgoing edges
   struct Edges {
     std::set<T> inc;
     std::set<T> out;
   };
-  std::map<T, Edges> E;
+  std::unordered_map<T, Edges> E;
 
   // Repair reachability trees after edge deletions
-  void repairTrees(std::map<T, std::stack<T>>& H);
+  void repairTrees(std::unordered_map<T, std::stack<T>>& H);
 };
 
 template<typename T>
@@ -68,7 +68,7 @@ template<typename T>
 void Italiano<T>::remove(const T& u, const T& v) {
   if (!this->G.adjList[u].contains(v)) return;
 
-  std::map<T, std::stack<T>> H;
+  std::unordered_map<T, std::stack<T>> H;
   for (const auto& w : this->G.vertices()) {
     if (RT[w].contains(u, v)) {
       if (E[v].inc.size() > 1)
@@ -89,7 +89,7 @@ void Italiano<T>::remove(const T& u, const T& v) {
 }
 
 template<typename T>
-void Italiano<T>::repairTrees(std::map<T, std::stack<T>>& H) {
+void Italiano<T>::repairTrees(std::unordered_map<T, std::stack<T>>& H) {
   for (const auto& z : this->G.vertices()) {
     while (H[z].size() > 0) {
       const auto& h = H[z].top();
diff --git a/algorithm/king.h b/algorithm/king.h
index d23991b..a41286a 100644
--- a/algorithm/king.h
+++ b/algorithm/king.h
@@ -31,8 +31,8 @@ public:
   void insert(const T& u, const T& v) override;
 private:
   // Connect each reachabiliy tree with decremental maintenance data structure
-  std::map<T, Italiano<T>> In;
-  std::map<T, Italiano<T>> Out;
+  std::unordered_map<T, Italiano<T>> In;
+  std::unordered_map<T, Italiano<T>> Out;
 };
 
 template<typename T>
diff --git a/algorithm/roditty_zwick.h b/algorithm/roditty_zwick.h
index 40a8968..aac52b1 100644
--- a/algorithm/roditty_zwick.h
+++ b/algorithm/roditty_zwick.h
@@ -28,17 +28,17 @@ public:
   // Remove edge (u,v) and update A accordingly for fast checking query
   void remove(const T& u, const T& v) override;
 
-  std::map<T, SCC<T>> getSCCs() { return C; }
+  std::unordered_map<T, SCC<T>> getSCCs() { return C; }
 private:
   // Array used to answer strong connectivity queries in O(1) time
-  std::map<T, T> A;
+  std::unordered_map<T, T> A;
 
   // Connect each representative with its SCC
-  std::map<T, SCC<T>> C;
+  std::unordered_map<T, SCC<T>> C;
 
   // Maintain in-out bfs trees
-  std::map<T, BreadthFirstTree<T>> In;
-  std::map<T, BreadthFirstTree<T>> Out;
+  std::unordered_map<T, BreadthFirstTree<T>> In;
+  std::unordered_map<T, BreadthFirstTree<T>> Out;
 };
 
 template<typename T>
diff --git a/algorithm/tarjan.h b/algorithm/tarjan.h
index 29a479e..018a8c8 100644
--- a/algorithm/tarjan.h
+++ b/algorithm/tarjan.h
@@ -16,7 +16,7 @@ class Tarjan {
 public:
   Tarjan() = default;
 
-  Tarjan(std::map<T, std::set<T>> adjList) : adjList(adjList) {}
+  Tarjan(std::unordered_map<T, std::unordered_set<T>> adjList) : adjList(adjList) {}
 
   //
   auto execute();
@@ -24,7 +24,7 @@ public:
   //
   void strongConnect(const T& u);
 private:
-  std::map<T, std::set<T>> adjList;
+  std::unordered_map<T, std::unordered_set<T>> adjList;
   std::stack<T> S;
   std::int16_t index = 0;
   std::vector<SCC<T>> SCCs;
@@ -35,7 +35,7 @@ private:
     int lowlink = -1;
     bool onStack = false;
   };
-  std::map<T, Vertex> vmap;
+  std::unordered_map<T, Vertex> vmap;
 };
 
 template<typename T>
@@ -55,7 +55,7 @@ void Tarjan<T>::strongConnect(const T& u) {
 
   // If u is a root node, pop the stack and generate an SCC
   if (vmap[u].lowlink == vmap[u].index) {
-    std::map<T, std::set<T>> scc;
+    std::unordered_map<T, std::unordered_set<T>> scc;
     bool finished = false;
     cid = S.top();
 
diff --git a/graph/breadth_first_tree.h b/graph/breadth_first_tree.h
index 1262400..f77be54 100644
--- a/graph/breadth_first_tree.h
+++ b/graph/breadth_first_tree.h
@@ -10,7 +10,7 @@ class BreadthFirstTree : public Digraph<T> {
 public:
   BreadthFirstTree() = default;
 
-  BreadthFirstTree(std::map<T, std::set<T>> G, T root)
+  BreadthFirstTree(std::unordered_map<T, std::unordered_set<T>> G, T root)
     : BreadthFirstTree<T>(Digraph<T>(G), root) {}
 
   BreadthFirstTree(Digraph<T> G, T root);
diff --git a/graph/digraph.h b/graph/digraph.h
index b2f76b0..4c2689e 100644
--- a/graph/digraph.h
+++ b/graph/digraph.h
@@ -11,7 +11,7 @@ class Digraph : public Graph<T> {
 public:
   Digraph() = default;
 
-  Digraph(std::map<T, std::set<T>> G);
+  Digraph(std::unordered_map<T, std::unordered_set<T>> G);
 
   // Return true if there is a path from u to v
   bool contains(const T& u, const T& v);
@@ -27,7 +27,7 @@ public:
 };
 
 template<typename T>
-Digraph<T>::Digraph(std::map<T, std::set<T>> G) {
+Digraph<T>::Digraph(std::unordered_map<T, std::unordered_set<T>> G) {
   this->adjList = G;
 }
 
@@ -49,7 +49,7 @@ void Digraph<T>::remove(const T& u, const T& v) {
 
 template<typename T>
 auto Digraph<T>::reverse() {
-  std::map<T, std::set<T>> revMatrix;
+  std::unordered_map<T, std::unordered_set<T>> revMatrix;
   
   for (const auto& u : this->vertices()) {
     for (const auto& v : this->adjList[u]) {
diff --git a/graph/graph.h b/graph/graph.h
index 29546f8..3968c8d 100644
--- a/graph/graph.h
+++ b/graph/graph.h
@@ -1,8 +1,8 @@
 #ifndef GRAPH_H_
 #define GRAPH_H_
 
-#include <map>
-#include <set>
+#include <unordered_map>
+#include <unordered_set>
 #include <ostream>
 #include <ranges>
 
@@ -36,7 +36,7 @@ public:
   std::uint16_t E();
 
   // Adjacency matrix representation
-  std::map<T, std::set<T>> adjList;
+  std::unordered_map<T, std::unordered_set<T>> adjList;
 
   friend std::ostream& operator<<<>(std::ostream& os, Graph<T>& G);
 };
diff --git a/graph/scc.h b/graph/scc.h
index a228726..8d51af1 100644
--- a/graph/scc.h
+++ b/graph/scc.h
@@ -13,7 +13,8 @@ class SCC : public Digraph<T> {
 public:
   SCC() = default;
 
-  SCC(std::map<T, std::set<T>> G, T id) : Digraph<T>(G), id(id) { normalize(); }
+  SCC(std::unordered_map<T, std::unordered_set<T>> G, T id)
+    : Digraph<T>(G), id(id) { normalize(); }
 
   SCC(Digraph<T> G, T id) : id(id) { normalize(); }
 
diff --git a/test/algorithm_test.cc b/test/algorithm_test.cc
index aee7fa1..7079bb5 100644
--- a/test/algorithm_test.cc
+++ b/test/algorithm_test.cc
@@ -109,7 +109,8 @@ TEST_SUITE("Algorithm") {
     auto tree =
       algo::BreadthFirstSearch<std::uint16_t>(G.adjList).execute(1);
 
-    std::map<std::uint16_t, std::set<std::uint16_t>> expected = {
+    std::unordered_map<std::uint16_t, 
+      std::unordered_set<std::uint16_t>> expected = {
       {1, {2}},
       {2, {3, 6}},
       {3, {4}},
diff --git a/test/graph_test.cc b/test/graph_test.cc
index f512cb7..f0a421a 100644
--- a/test/graph_test.cc
+++ b/test/graph_test.cc
@@ -39,7 +39,8 @@ TEST_SUITE("Graph") {
 
     auto reverse = G.reverse();
 
-    std::map<std::uint16_t, std::set<std::uint16_t>> expected = {
+    std::unordered_map<std::uint16_t,
+      std::unordered_set<std::uint16_t>> expected = {
       {1, {3}},
       {2, {1}},
       {3, {2, 5}},