create 0807 folder & cpp solution

Author: zouwx2cs

solution/0807.Max Increase to Keep City Skyline/Solution.cpp

@@ -0,0 +1,29 @@
+class Solution {
+public:
+    int maxIncreaseKeepingSkyline(vector<vector<int>>& grid) 
+    {
+
+        vector<int> h(grid.size(), -1), w(grid[0]) ;
+        
+        for (int i = 0; i < grid.size(); ++i)
+            for (int j = 0; j < grid[i].size(); ++j)
+            {
+                if (grid[i][j] > h[i])
+                    h[i] = grid[i][j] ;
+                if (grid[i][j] > w[j])
+                    w[j] = grid[i][j] ;
+            }
+        int sum = 0 ;
+        
+        for (int i = 0; i < grid.size(); ++i)
+            for (int j = 0; j < grid.size(); ++j)
+            {
+                int m = h[i] < w[j]? h[i]: w[j] ;
+                if (grid[i][j] < m)
+                    sum += m - grid[i][j] ;
+            }
+        
+        
+        return sum ;
+    }
+};