unit test for hashmap

Author: chen0040

README.md

@@ -117,3 +117,28 @@ print(s:delMax()) -- return 10
 print(s:isEmpty()) -- return true
 ```
 
+### HashMap
+
+```lua
+local hashmap = require('data.hashmap')
+local hash_func = function(x) return x % 1000 end
+local s = hashmap.create(hash_func)
+s:put(100, 2)
+s:put(200, 4)
+s:put(450, 2)
+print(s:get(100)) -- return  2
+print(s:get(200)) -- return  4
+print(s:get(450)) -- return  2
+print(s:get(99)) -- return  nil
+print(s:containsKey(99)) -- return  false
+print(s:containsKey(100)) -- return  true
+print(s:size()) -- return  3
+print(s:isEmpty()) -- return  false
+print(s:remove(100)) -- return  2
+print(s:containsKey(100)) -- return  false
+print(s:size()) -- return  2
+s:remove(200)
+s:remove(450)
+print(s:isEmpty()) -- return  true
+```
+

spec/hashmap_spec.lua

@@ -0,0 +1,35 @@
+--
+-- Created by IntelliJ IDEA.
+-- User: chen0
+-- Date: 26/6/2017
+-- Time: 12:03 PM
+-- To change this template use File | Settings | File Templates.
+--
+
+describe('hashmap', function()
+    describe('hashmap()', function()
+        it('should put and get and remove correctly', function()
+            local hashmap = require('data.hashmap')
+            local hash_func = function(x) return x % 1000 end
+            local s = hashmap.create(hash_func)
+            s:put(100, 2)
+            s:put(200, 4)
+            s:put(450, 2)
+            assert.equal(s:get(100), 2)
+            assert.equal(s:get(200), 4)
+            assert.equal(s:get(450), 2)
+            assert.equal(s:get(99), nil)
+            assert.equal(s:containsKey(99), false)
+            assert.equal(s:containsKey(100), true)
+            assert.equal(s:size(), 3)
+            assert.equal(s:isEmpty(), false)
+            assert.equal(s:remove(100), 2)
+            assert.equal(s:containsKey(100), false)
+            assert.equal(s:size(), 2)
+            s:remove(200)
+            s:remove(450)
+            assert.equal(s:isEmpty(), true)
+        end)
+    end)
+end)
+

src/data/hashmap.lua

@@ -34,12 +34,13 @@ function hashmap.create(hash)
 
     s.s = {}
     s.N = 0
+    s.hash = hash
 
     return s
 end
 
 function hashmap:put(key, value)
-    local h = self:hash(key)
+    local h = self.hash(key)
     local x = self.s[h]
     local found = false
     while x ~= nil do
@@ -61,7 +62,7 @@ function hashmap:put(key, value)
 end
 
 function hashmap:get(key)
-    local h = self:hash(key)
+    local h = self.hash(key)
     local x = self.s[h]
     while x ~= nil do
         if x.key == key then
@@ -73,7 +74,7 @@ function hashmap:get(key)
 end
 
 function hashmap:containsKey(key)
-    local h = self:hash(key)
+    local h = self.hash(key)
     local x = self.s[h]
     while x ~= nil do
         if x.key == key then
@@ -88,12 +89,12 @@ function hashmap:size()
     return self.N
 end
 
-function hashmap:isEmpy()
+function hashmap:isEmpty()
     return self.N == 0
 end
 
 function hashmap:remove(key)
-    local h = self:hash(key)
+    local h = self.hash(key)
     local x = self.s[h]
     local prev_x = nil
     while x ~= nil do
@@ -104,6 +105,7 @@ function hashmap:remove(key)
             else
                 prev_x.next = x.next
             end
+            self.N = self.N - 1
             return value
         end
         prev_x = x