Update and rename 496.Next Greater Element I.cpp to 496.Next-Greater-…

…Element-I.cpp
thisistrue1 · Dec 19, 2021 · 4523734 · 4523734
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diff --git a/Stack/496.Next-Greater-Element-I/496.Next Greater Element I.cpp b/Stack/496.Next-Greater-Element-I/496.Next Greater Element I.cpp
diff --git a/Stack/496.Next-Greater-Element-I/496.Next-Greater-Element-I.cpp b/Stack/496.Next-Greater-Element-I/496.Next-Greater-Element-I.cpp
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+class Solution {
+    unordered_map<int,int>nextGreater;
+public:
+    vector<int> nextGreaterElement(vector<int>& nums1, vector<int>& nums2) 
+    {
+        int n = nums2.size();
+        stack<int>Stack;  // index
+        for (int i = 0; i < n; i++)
+        {
+            while (!Stack.empty() && nums2[Stack.top()] < nums2[i])
+            {
+                nextGreater[nums2[Stack.top()]] = nums2[i];
+                Stack.pop();
+            }
+            Stack.push(i);
+        }
+
+        vector<int>rets;
+        for (int x: nums1)
+        {
+            if (nextGreater.find(x)==nextGreater.end())
+                rets.push_back(-1);
+            else
+                rets.push_back(nextGreater[x]);
+        }
+        return rets;        
+    }
+};