5 April 2017:496.Next Greater Element I

Jack-Cherish · Jack-Cherish · commit 5f5f7f38e350 · 2017-04-05T21:56:21.000+08:00
diff --git a/Stack/Easy/496. Next Greater Element I/Next Greater Element I.cpp b/Stack/Easy/496. Next Greater Element I/Next Greater Element I.cpp
@@ -0,0 +1,22 @@
+class Solution {
+public:
+    vector<int> nextGreaterElement(vector<int>& findNums, vector<int>& nums) {
+        stack<int> s;
+        unordered_map<int, int> m;
+        //遍历nums中的元素
+        for (auto e : nums){
+            //堆栈s为空并且堆栈s的栈顶的元素小于e元素,将元素写入map中,key值为栈顶元素,value值为比栈顶元素大的元素
+            while(!s.empty() && s.top() < e){
+                m[s.top()] = e;
+                s.pop();
+            }
+            s.push(e);
+        }
+        vector<int> ans;
+        //查找findNums中元素,如果m中存在n,返回m[n]的valuse值,如果不存在返回-1
+        for (auto n : findNums){
+            ans.push_back(m.count(n) ? m[n] : -1);
+        }
+        return ans;
+    }
+};
diff --git a/Stack/Easy/496.Next Greater Element I/Next Greater Element I.cpp b/Stack/Easy/496.Next Greater Element I/Next Greater Element I.cpp
@@ -0,0 +1,22 @@
+class Solution {
+public:
+    vector<int> nextGreaterElement(vector<int>& findNums, vector<int>& nums) {
+        stack<int> s;
+        unordered_map<int, int> m;
+        //遍历nums中的元素
+        for (auto e : nums){
+            //堆栈s为空并且堆栈s的栈顶的元素小于e元素,将元素写入map中,key值为栈顶元素,value值为比栈顶元素大的元素
+            while(!s.empty() && s.top() < e){
+                m[s.top()] = e;
+                s.pop();
+            }
+            s.push(e);
+        }
+        vector<int> ans;
+        //查找findNums中元素,如果m中存在n,返回m[n]的valuse值,如果不存在返回-1
+        for (auto n : findNums){
+            ans.push_back(m.count(n) ? m[n] : -1);
+        }
+        return ans;
+    }
+};
