diff --git a/src/k_clustering_big.rs b/src/k_clustering_big.rs
index 22628e6..01a8906 100644
--- a/src/k_clustering_big.rs
+++ b/src/k_clustering_big.rs
@@ -1,19 +1,103 @@
-pub struct ImpliciteGraph {
-    pub nodes: Vec<Vec<usize>>,
-}
+use std::collections::HashMap;
+pub type ImpliciteGraph = Vec<u32>;
 
-fn distance(a: &Vec<usize>, b: &Vec<usize>) -> u16 {
-    let mut distance = 0;
-
-    for i in 0..a.len() {
-        if a[i] != b[i] {
-            distance += 1;
+#[allow(dead_code)]
+fn distance(a: &u32, b: &u32) -> u32 {
+    let mut r = 0;
+    for i in 0..24 {
+        let m = 0x1 << i;
+        if a & m != b & m {
+            r += 1;
         }
     }
-    distance
+    r
+}
+
+#[allow(dead_code)]
+fn neighbors_distance_1(a: u32) -> Vec<u32> {
+    let mut r = Vec::new();
+    for i in 0..24 {
+        let m = 0x1 << i;
+        let neighbor = a ^ m;
+        r.push(neighbor);
+    }
+    r
+}
+
+#[allow(dead_code)]
+fn neighbors_distance_2(a: u32) -> Vec<u32> {
+    let mut r = Vec::new();
+    for i in 0..24 {
+        let m = 0x1 << i;
+        let n1 = a ^ m;
+        for j in 0..24 {
+            let m = 0x1 << j;
+            let n2 = n1 ^ m;
+            if n2 != a {
+                r.push(n2);
+            }
+        }
+    }
+    r.sort();
+    r.dedup();
+    r
 }
 
 pub fn k_clustering_big(g: &ImpliciteGraph) -> usize {
-    println!("distance: {:?}", distance(&g.nodes[0], &g.nodes[1]));
-    g.nodes.len()
+    let mut node_id_to_cluster_id: Vec<usize> = (0..g.len()).collect();
+    let mut clusters: Vec<Vec<usize>> = (0..g.len()).map(|x| vec![x]).collect();
+    let mut node_map: HashMap<u32, Vec<usize>> = HashMap::new();
+    let mut cluster_count = g.len();
+
+    for i in 0..g.len() {
+        if let Some(x) = node_map.get_mut(&g[i]) {
+            x.push(i);
+        } else {
+            node_map.insert(g[i], vec![i]);
+        }
+    }
+
+    for node_a_id in 0..g.len() {
+        for node_b_value in neighbors_distance_1(g[node_a_id]) {
+            if let Some(node_b_ids) = node_map.get(&node_b_value) {
+                // These node IDs have distance one meaning we want to merge them into
+                // the same cluster.
+                for node_b_id in node_b_ids {
+                    let cluster_id_a = node_id_to_cluster_id[node_a_id];
+                    let cluster_id_b = node_id_to_cluster_id[*node_b_id];
+                    if cluster_id_a != cluster_id_b {
+                        // Merge b into a because nodes have distance 1.
+                        let mut cluster_b = std::mem::take(&mut clusters[cluster_id_b]);
+                        for node_id in &cluster_b {
+                            node_id_to_cluster_id[*node_id] = cluster_id_a;
+                        }
+                        clusters[cluster_id_a].append(&mut cluster_b);
+                        cluster_count -= 1;
+                    }
+                }
+            }
+        }
+
+        for node_b_value in neighbors_distance_2(g[node_a_id]) {
+            if let Some(node_b_ids) = node_map.get(&node_b_value) {
+                // These node IDs have distance one meaning we want to merge them into
+                // the same cluster.
+                for node_b_id in node_b_ids {
+                    let cluster_id_a = node_id_to_cluster_id[node_a_id];
+                    let cluster_id_b = node_id_to_cluster_id[*node_b_id];
+                    if cluster_id_a != cluster_id_b {
+                        // Merge b into a because nodes have distance 2.
+                        let mut cluster_b = std::mem::take(&mut clusters[cluster_id_b]);
+                        for node_id in &cluster_b {
+                            node_id_to_cluster_id[*node_id] = cluster_id_a;
+                        }
+                        clusters[cluster_id_a].append(&mut cluster_b);
+                        cluster_count -= 1;
+                    }
+                }
+            }
+        }
+    }
+
+    cluster_count
 }
diff --git a/src/util.rs b/src/util.rs
index 8a5e9f7..18b0b9d 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -234,19 +234,17 @@ pub fn read_k_cluster_big(path: &str) -> Result<k_clustering_big::ImpliciteGraph
     let bits_per_node: usize = fields.next().unwrap().parse().unwrap();
 
     println!(
-        "total_nodes = {:?}\nbits_per_node = {:?}",
+        "total_nodes = {:?} bits_per_node = {:?}",
         total_nodes, bits_per_node
     );
 
-    let mut g = k_clustering_big::ImpliciteGraph { nodes: vec![] };
+    let mut g = Vec::new();
 
     for line in lines {
-        let line = line?;
-        let v: Vec<usize> = line
-            .split_whitespace()
-            .map(|s| s.parse().unwrap())
-            .collect();
-        g.nodes.push(v);
+        let mut s = line?;
+        s.retain(|c| !c.is_whitespace());
+        let u = u32::from_str_radix(&s, 2).unwrap();
+        g.push(u);
     }
 
     Ok(g)