498. Diagonal Traverse

498. Diagonal Traverse solved

README.md

@@ -138,6 +138,7 @@
 |0455|[Arithmetic Slices II - Subsequence](https://leetcode.com/problems/arithmetic-slices-ii-subsequence/) | [Python3](/Solutions/0446_Arithmetic_Slices_II_Subsequence.py) | Hard |
 |0455|[Assign Cookies](https://leetcode.com/problems/assign-cookies/) | [Python3](/Solutions/0455_Assign_Cookies.py) | Easy |
 |0459|[Repeated Substring Pattern](https://leetcode.com/problems/repeated-substring-pattern/) | [Python3](/Solutions/0459_Repeated_Substring_Pattern.py) | Easy |
+|0498|[Diagonal Traverse](https://leetcode.com/problems/diagonal-traverse/) | [Python3](/Solutions/0498_Diagonal_Traverse.py) | Medium |
 |0501|[Repeated Substring Pattern](https://leetcode.com/problems/find-mode-in-binary-search-tree/) | [Python3](/Solutions/0501_Find_Mode_in_Binary_Search_Tree.py) | Easy |
 |0515|[Find Largest Value in Each Tree Row](https://leetcode.com/problems/find-largest-value-in-each-tree-row/) | [Python3](/Solutions/0515_Find_Largest_Value_in_Each_Tree_Row.py) | Medium |
 |0523|[Continuous Subarray Sum](https://leetcode.com/problems/continuous-subarray-sum/) | [Python3](/Solutions/0523_Continuous_Subarray_Sum.py) | Medium |

Solutions/0498_Diagonal_Traverse.py

@@ -0,0 +1,38 @@
+class Solution:
+    def findDiagonalOrder(self, mat: List[List[int]]) -> List[int]:
+        n_row = len(mat) # num of row
+        n_col = len(mat[0]) # num of column
+
+        # List reserve List[List[int]]
+        sol_list = []
+
+        # start with top row
+        for row in range(n_row):
+            temp_list = []
+            for col in range(n_col):
+                if row < 0:
+                    break
+                temp_list = [mat[row][col]] + temp_list
+                row -= 1
+            sol_list.append(temp_list)
+
+        # start with right column
+        for col in range(1, n_col):
+            temp_list = []
+            for row in range(n_row):
+                if col >= n_col:
+                    break
+                temp_list = [mat[n_row - row - 1][col]] + temp_list
+                col += 1
+            sol_list.append(temp_list)
+
+        # organize sol_list
+        sol = []
+        isReversed = True
+        for each_sol_list in sol_list:
+            if isReversed:
+                sol += each_sol_list[::-1]
+            else:
+                sol += each_sol_list
+            isReversed = isReversed == False
+        return sol