diff --git a/EditDistance.xcodeproj/project.pbxproj b/EditDistance.xcodeproj/project.pbxproj
index c325d9d..5dbc4cd 100644
--- a/EditDistance.xcodeproj/project.pbxproj
+++ b/EditDistance.xcodeproj/project.pbxproj
@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		2B6BD4CF22B49BDC00C68FCA /* EDCollectionViewDiffableDataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2B6BD4CE22B49BDC00C68FCA /* EDCollectionViewDiffableDataSource.swift */; };
 		2BC5BC0E1F86798300D7F4B9 /* EditDistance.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6EBF3E901E59C2FB0025443A /* EditDistance.swift */; };
 		2BC5BC0F1F86798500D7F4B9 /* EditDistanceContainer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6E0301661E61689200E24C49 /* EditDistanceContainer.swift */; };
 		2BC5BC101F86798800D7F4B9 /* EditScriptConverter.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6EBF3E461E5854C70025443A /* EditScriptConverter.swift */; };
@@ -67,6 +68,7 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
+		2B6BD4CE22B49BDC00C68FCA /* EDCollectionViewDiffableDataSource.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EDCollectionViewDiffableDataSource.swift; sourceTree = "<group>"; };
 		6E0301661E61689200E24C49 /* EditDistanceContainer.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = EditDistanceContainer.swift; sourceTree = "<group>"; };
 		6E0301681E619DB300E24C49 /* WuTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = WuTests.swift; sourceTree = "<group>"; };
 		6E03016C1E61A8B000E24C49 /* DynamicProgrammingTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DynamicProgrammingTests.swift; sourceTree = "<group>"; };
@@ -130,6 +132,7 @@
 				6EBF3E961E59C3BE0025443A /* EditScriptConverterProxy.swift */,
 				6EBF3E921E59C3640025443A /* EditScriptConverterProxy+UITableView.swift */,
 				6EBF3E941E59C3830025443A /* EditScriptConverterProxy+UICollectionView.swift */,
+				2B6BD4CE22B49BDC00C68FCA /* EDCollectionViewDiffableDataSource.swift */,
 			);
 			name = Converter;
 			sourceTree = "<group>";
@@ -420,6 +423,7 @@
 				6EBF3EF21E5C79330025443A /* EditDistanceAlgorithmContainer.swift in Sources */,
 				6E0301671E61689200E24C49 /* EditDistanceContainer.swift in Sources */,
 				6EBF3E4D1E58553C0025443A /* Wu.swift in Sources */,
+				2B6BD4CF22B49BDC00C68FCA /* EDCollectionViewDiffableDataSource.swift in Sources */,
 				6EBF3E471E5854C70025443A /* EditScriptConverter.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -580,6 +584,7 @@
 				SDKROOT = iphoneos;
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = DEBUG;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VERSIONING_SYSTEM = "apple-generic";
 				VERSION_INFO_PREFIX = "";
@@ -634,6 +639,7 @@
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
 				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VALIDATE_PRODUCT = YES;
 				VERSIONING_SYSTEM = "apple-generic";
diff --git a/EditDistance/EDCollectionViewDiffableDataSource.swift b/EditDistance/EDCollectionViewDiffableDataSource.swift
new file mode 100644
index 0000000..bc64324
--- /dev/null
+++ b/EditDistance/EDCollectionViewDiffableDataSource.swift
@@ -0,0 +1,181 @@
+//
+//  EDCollectionViewDiffableDataSource.swift
+//  EditDistance
+//
+//  Created by Kazuhiro Hayashi on 6/15/1 R.
+//  Copyright © 2019 Kazuhiro Hayashi. All rights reserved.
+//
+
+import UIKit
+
+public class EDCollectionViewDiffableDataSource<SectionIdentifierType, ItemIdentifierType> : NSObject, UICollectionViewDataSource where SectionIdentifierType : Hashable, ItemIdentifierType : Hashable {
+    
+    private var currentDataSource = [SectionIdentifierType: [ItemIdentifierType]]()
+    private let cellProvider: EDCollectionViewDiffableDataSource<SectionIdentifierType, ItemIdentifierType>.CellProvider
+    private let collectionView: UICollectionView
+    
+    public typealias CellProvider = (UICollectionView, IndexPath, ItemIdentifierType) -> UICollectionViewCell?
+    
+    public typealias SupplementaryViewProvider = (UICollectionView, String, IndexPath) -> UICollectionReusableView?
+    
+    public var supplementaryViewProvider: EDCollectionViewDiffableDataSource<SectionIdentifierType, ItemIdentifierType>.SupplementaryViewProvider? {
+        
+    }
+    
+    public init(collectionView: UICollectionView, cellProvider: @escaping EDCollectionViewDiffableDataSource<SectionIdentifierType, ItemIdentifierType>.CellProvider) {
+        self.collectionView = collectionView
+        self.cellProvider = cellProvider
+        super.init()
+    }
+    
+    public func apply(_ snapshot: EDDiffableDataSourceSnapshot<SectionIdentifierType, ItemIdentifierType>, animatingDifferences: Bool = true) {
+        currentDataSource
+    }
+    
+    public func snapshot() -> EDDiffableDataSourceSnapshot<SectionIdentifierType, ItemIdentifierType> {
+        
+    }
+    
+    public func itemIdentifier(for indexPath: IndexPath) -> ItemIdentifierType? {
+        
+    }
+    
+    // TODO:- items needs search from Hashable
+    public func indexPath(for itemIdentifier: ItemIdentifierType) -> IndexPath? {
+        let sections = Array(currentDataSource.keys.enumerated())
+        var indexPath: IndexPath?
+        
+        for section in sections {
+            let items = currentDataSource[section.element]
+            if let item = items?.enumerated().first(where: { $0.element == itemIdentifier }) {
+                indexPath = IndexPath(item: item.offset, section: section.offset)
+                break
+            }
+        }
+        return indexPath
+    }
+    
+    public func numberOfSections(in collectionView: UICollectionView) -> Int {
+        return currentDataSource.keys.count
+    }
+    
+    public func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
+        let sectionKey = Array(currentDataSource.keys)[section]
+        return currentDataSource[sectionKey]?.count ?? 0
+    }
+    
+    public func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
+        let sectionKey = Array(currentDataSource.keys)[indexPath.section]
+        let item = currentDataSource[sectionKey][indexPath.row]
+        return cellProvider(collectionView, indexPath, item)
+    }
+    
+    public func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
+        
+    }
+}
+
+public class EDDiffableDataSourceSnapshot<SectionIdentifierType, ItemIdentifierType> where SectionIdentifierType : Hashable, ItemIdentifierType : Hashable {
+    
+    private var newDataSource: [SectionIdentifierType: [ItemIdentifierType]]
+    
+    public init() {
+        
+    }
+    
+    public var numberOfItems: Int {
+        
+    }
+    
+    public var numberOfSections: Int {
+        
+    }
+    
+    public var sectionIdentifiers: [SectionIdentifierType] {
+        
+    }
+    
+    public var itemIdentifiers: [ItemIdentifierType] {
+        
+    }
+    
+    public func numberOfItems(inSection identifier: SectionIdentifierType) -> Int {
+        
+    }
+    
+    public func itemIdentifiers(inSection identifier: SectionIdentifierType) -> [ItemIdentifierType] {
+        
+    }
+    
+    public func sectionIdentifier(containingItem identifier: ItemIdentifierType) -> SectionIdentifierType? {
+        
+    }
+    
+    public func indexOfItem(_ identifier: ItemIdentifierType) -> Int? {
+        
+    }
+    
+    public func indexOfSection(_ identifier: SectionIdentifierType) -> Int? {
+        
+    }
+    
+    public func appendItems(_ identifiers: [ItemIdentifierType], toSection sectionIdentifier: SectionIdentifierType? = nil) {
+        
+    }
+    
+    public func insertItems(_ identifiers: [ItemIdentifierType], beforeItem beforeIdentifier: ItemIdentifierType) {
+        
+    }
+    
+    public func insertItems(_ identifiers: [ItemIdentifierType], afterItem afterIdentifier: ItemIdentifierType) {
+        
+    }
+    
+    public func deleteItems(_ identifiers: [ItemIdentifierType]) {
+        
+    }
+    
+    public func deleteAllItems() {
+        
+    }
+    
+    public func moveItem(_ identifier: ItemIdentifierType, beforeItem toIdentifier: ItemIdentifierType) {
+        
+    }
+    
+    public func moveItem(_ identifier: ItemIdentifierType, afterItem toIdentifier: ItemIdentifierType) {
+        
+    }
+    
+    public func reloadItems(_ identifiers: [ItemIdentifierType]) {
+        
+    }
+    
+    public func appendSections(_ identifiers: [SectionIdentifierType]) {
+        
+    }
+    
+    public func insertSections(_ identifiers: [SectionIdentifierType], beforeSection toIdentifier: SectionIdentifierType) {
+        
+    }
+    
+    public func insertSections(_ identifiers: [SectionIdentifierType], afterSection toIdentifier: SectionIdentifierType) {
+        
+    }
+    
+    public func deleteSections(_ identifiers: [SectionIdentifierType]) {
+        
+    }
+    
+    public func moveSection(_ identifier: SectionIdentifierType, beforeSection toIdentifier: SectionIdentifierType) {
+        
+    }
+    
+    public func moveSection(_ identifier: SectionIdentifierType, afterSection toIdentifier: SectionIdentifierType) {
+        
+    }
+    
+    public func reloadSections(_ identifiers: [SectionIdentifierType]) {
+        
+    }
+}
diff --git a/iOS Example/iOS Example.xcodeproj/project.pbxproj b/iOS Example/iOS Example.xcodeproj/project.pbxproj
index a7f1169..8f611a1 100644
--- a/iOS Example/iOS Example.xcodeproj/project.pbxproj	
+++ b/iOS Example/iOS Example.xcodeproj/project.pbxproj	
@@ -397,6 +397,7 @@
 				SDKROOT = iphoneos;
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = DEBUG;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -448,6 +449,7 @@
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
 				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VALIDATE_PRODUCT = YES;
 			};