diff --git a/56-LEETCODE-SOLUTION-Merge-interval.java b/56-LEETCODE-SOLUTION-Merge-interval.java
deleted file mode 100644
index 206067a3..00000000
--- a/56-LEETCODE-SOLUTION-Merge-interval.java
+++ /dev/null
@@ -1,93 +0,0 @@
-class Solution {
-    private Map<int[], List<int[]>> graph;
-    private Map<Integer, List<int[]>> nodesInComp;
-    private Set<int[]> visited;
-
-    // return whether two intervals overlap (inclusive)
-    private boolean overlap(int[] a, int[] b) {
-        return a[0] <= b[1] && b[0] <= a[1];
-    }
-
-    // build a graph where an undirected edge between intervals u and v exists
-    // iff u and v overlap.
-    private void buildGraph(int[][] intervals) {
-        graph = new HashMap<>();
-        for (int[] interval : intervals) {
-            graph.put(interval, new LinkedList<>());
-        }
-
-        for (int[] interval1 : intervals) {
-            for (int[] interval2 : intervals) {
-                if (overlap(interval1, interval2)) {
-                    graph.get(interval1).add(interval2);
-                    graph.get(interval2).add(interval1);
-                }
-            }
-        }
-    }
-
-    // merges all of the nodes in this connected component into one interval.
-    private int[] mergeNodes(List<int[]> nodes) {
-        int minStart = nodes.get(0)[0];
-        for (int[] node : nodes) {
-            minStart = Math.min(minStart, node[0]);
-        }
-
-        int maxEnd = nodes.get(0)[1];
-        for (int[] node : nodes) {
-            maxEnd = Math.max(maxEnd, node[1]);
-        }
-
-        return new int[] {minStart, maxEnd};
-    }
-
-    // use depth-first search to mark all nodes in the same connected component
-    // with the same integer.
-    private void markComponentDFS(int[] start, int compNumber) {
-        Stack<int[]> stack = new Stack<>();
-        stack.add(start);
-
-        while (!stack.isEmpty()) {
-            int[] node = stack.pop();
-            if (!visited.contains(node)) {
-                visited.add(node);
-
-                if (nodesInComp.get(compNumber) == null) {
-                    nodesInComp.put(compNumber, new LinkedList<>());
-                }
-                nodesInComp.get(compNumber).add(node);
-
-                for (int[] child : graph.get(node)) {
-                    stack.add(child);
-                }
-            }
-        }
-    }
-
-    // gets the connected components of the interval overlap graph.
-    private void buildComponents(int[][] intervals) {
-        nodesInComp = new HashMap<>();
-        visited = new HashSet<>();
-        int compNumber = 0;
-
-        for (int[] interval : intervals) {
-            if (!visited.contains(interval)) {
-                markComponentDFS(interval, compNumber);
-                compNumber++;
-            }
-        }
-    }
-
-    public int[][] merge(int[][] intervals) {
-        buildGraph(intervals);
-        buildComponents(intervals);
-
-        // for each component, merge all intervals into one interval.
-        List<int[]> merged = new LinkedList<>();
-        for (int comp = 0; comp < nodesInComp.size(); comp++) {
-            merged.add(mergeNodes(nodesInComp.get(comp)));
-        }
-
-        return merged.toArray(new int[merged.size()][]);
-    }
-}