Added problem 594 and 217

217_duplicate/hash.cpp

@@ -0,0 +1,22 @@
+#include <vector>
+#include <unordered_set>
+
+class Solution {
+public:
+    bool containsDuplicate(std::vector<int>& nums) {
+        bool result = false;
+        std::unordered_set<int> set;
+        for (int num : nums)
+        {
+            auto find_result = set.find(num);
+            if (find_result == set.end())
+                set.insert(num);
+            else
+            {
+                result = true;
+                break;
+            }
+        }
+        return result;
+    }
+};

594_harmonious/hashing.cpp

@@ -0,0 +1,29 @@
+#include <vector>
+#include <unordered_map>
+#include <math.h>
+
+class Solution {
+public:
+    int findLHS(std::vector<int>& nums) {
+        int result = 0;
+        std::unordered_map<int, int> map;
+        for (int num : nums)
+        {
+            auto find_result = map.find(num);
+            if (find_result == map.end())
+                map.emplace(num,1);
+            else 
+                find_result->second ++;
+        }
+        for (auto iterat = map.begin(); iterat != map.end(); iterat ++)
+        {
+            auto find_result = map.find(iterat->first + 1);
+            if (find_result != map.end())
+                {
+                    int temp = iterat -> second + find_result -> second;
+                    result = std::max(result, temp);
+                }
+        }
+        return result;
+    }
+};

739_T/stack.cpp

@@ -11,22 +11,11 @@ class Solution
         std::vector<int> ans(size + 1, 0);
         while (size >= 0)
         {
-            if (s1.empty())
+            while (!s1.empty() && T.at(size) >= T.at(s1.top()))
             {
-                ans.at(size) = 0;
-            }
-            else if (T.at(size) > T.at(s1.top()))
-            {
-                while (!s1.empty() && T.at(size) > T.at(s1.top()))
-                {
-                    s1.pop();
-                }
-                ans.at(size) = !s1.empty() ? s1.top() - size : 0;
-            }
-            else
-            {
-                ans.at(size) = s1.top() - size;
+                s1.pop();
             }
+            ans.at(size) = !s1.empty() ? s1.top() - size : 0;
             s1.push(size);
             size--;
         }