Create WhereWilltheBallFall.cpp

algorithms/cpp/WhereWilltheBallFall/WhereWilltheBallFall.cpp

@@ -0,0 +1,32 @@
+// https://leetcode.com/problems/where-will-the-ball-fall/
+
+class Solution {
+public:
+    vector<int> findBall(vector<vector<int>>& grid) {
+        int N = grid.size();
+        int M = grid[0].size();
+        vector<int> res;
+
+        for(int ball=0;ball<grid[0].size();ball++){
+            int i = 0;
+            int j = ball;
+            while(i < N){
+                int cell = grid[i][j];
+				        // go left or right according to current cell (1 or -1)
+                j += cell;
+                // if got out of matrix
+                if(j >= M || j < 0)
+                    break;
+                // if adjacent cell is closed (eg. going left and current is right)
+                if(cell != grid[i][j])
+                    break;
+                // go down one cell
+                i++;
+            }
+            // if got out safely. push column num ( j ) else push ( -1 )
+            i == N ? res.push_back(j) : res.push_back(-1);
+        }
+        return res;
+    }
+};
+