Create 2282.Number-of-People-That-Can-Be-Seen-in-a-Grid.cpp

Stack/2282.Number-of-People-That-Can-Be-Seen-in-a-Grid/2282.Number-of-People-That-Can-Be-Seen-in-a-Grid.cpp

@@ -0,0 +1,52 @@
+class Solution {
+public:
+    vector<vector<int>> seePeople(vector<vector<int>>& heights) 
+    {        
+        int m = heights.size(), n = heights[0].size();
+        vector<vector<int>>rets(m, vector<int>(n,0));
+
+        for (int i=0; i<m; i++)
+        {
+            stack<int>stk;            
+            for (int j=0; j<n; j++)
+            {
+                int lastRemove = -1;
+                while (!stk.empty() && heights[i][j] >= heights[i][stk.top()])
+                {
+                    rets[i][stk.top()]++;
+                    lastRemove = heights[i][stk.top()];
+                    stk.pop();
+                }
+                if (!stk.empty() && lastRemove != heights[i][j])
+                {
+                    rets[i][stk.top()]++;                    
+                }
+                stk.push(j);
+            }
+
+        }           
+
+        for (int j=0; j<n; j++)
+        {
+            stack<int>stk;            
+            for (int i=0; i<m; i++)
+            {
+                int lastRemove = -1;
+                while (!stk.empty() && heights[i][j] >= heights[stk.top()][j])
+                {
+                    rets[stk.top()][j]++;
+                    lastRemove = heights[stk.top()][j];
+                    stk.pop();
+                }                
+                if (!stk.empty() && lastRemove != heights[i][j])
+                {
+                    rets[stk.top()][j]++;                    
+                }                
+                stk.push(i);
+            }
+        }
+
+        return rets;
+
+    }
+};