Create design-hashmap.cpp

Author: kamyu104

C++/design-hashmap.cpp

@@ -0,0 +1,55 @@
+// Time:  O(1)
+// Space: O(n)
+
+class MyHashMap {
+public:
+    /** Initialize your data structure here. */
+    MyHashMap() : data_(10000) {
+        
+    }
+    
+    /** value will always be positive. */
+    void put(int key, int value) {
+        auto& list = data_[key % data_.size()];
+        auto it = find_if(list.begin(), list.end(),
+                          [&](const pair<int, int>& i) { return i.first == key; } );
+        if (it != list.end()) {
+            it->second = value;
+        } else {
+            list.emplace_back(key, value);
+        }
+    }
+    
+    /** Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key */
+    int get(int key) {
+        auto& list = data_[key % data_.size()];
+        auto it = find_if(list.begin(), list.end(),
+                          [&](const pair<int, int>& i) { return i.first == key; } );
+        if (it != list.end()) {
+            return it->second;
+        } else {
+            return -1;
+        }
+    }
+    
+    /** Removes the mapping of the specified value key if this map contains a mapping for the key */
+    void remove(int key) {
+        auto& list = data_[key % data_.size()];
+        auto it = find_if(list.begin(), list.end(),
+                          [&](const pair<int, int>& i) { return i.first == key; } );
+        if (it != list.end()) {
+            list.erase(it);
+        }
+    }
+
+private:
+    vector<list<pair<int, int>>> data_;
+};
+
+/**
+ * Your MyHashMap object will be instantiated and called as such:
+ * MyHashMap obj = new MyHashMap();
+ * obj.put(key,value);
+ * int param_2 = obj.get(key);
+ * obj.remove(key);
+ */