Leetcode accepted

PriyankaKhire · PriyankaKhire · commit 91b049e3bef6 · 2021-08-22T22:16:42.000-07:00
diff --git a/Blind 75/Programs/Spiral Matrix.py b/Blind 75/Programs/Spiral Matrix.py
@@ -0,0 +1,59 @@
+# Spiral Matrix
+# https://leetcode.com/problems/spiral-matrix/
+
+class Boundries(object):
+    def __init__(self):
+        self.rowStart = None
+        self.rowEnd = None
+        self.colStart = None
+        self.colEnd = None
+        
+class Solution(object):
+    
+    # shrink boundries of the matrix for spiral print.
+    def setBoundries(self, matrix, decreaseBy):
+        boundries = Boundries()
+        # set row boundry
+        boundries.rowStart = 0 + decreaseBy
+        boundries.rowEnd = len(matrix) - decreaseBy
+        # set column boundry
+        boundries.colStart = 0 + decreaseBy
+        boundries.colEnd = len(matrix[0]) - decreaseBy
+        return boundries
+    
+    def markCellVisitedAddToSpiralPrint(self, matrix, row, col, spiralPrint):
+        # if the cell has not been visited
+        if (matrix[row][col] != "visited"):
+            spiralPrint.append(matrix[row][col])
+        # mark the cell visited
+        matrix[row][col] = "visited"
+        
+    def printSpiral(self, matrix, boundries, spiralPrint):
+        # print first row
+        for col in range(boundries.colStart, boundries.colEnd):
+            self.markCellVisitedAddToSpiralPrint(matrix, boundries.rowStart, col, spiralPrint)
+        # print last col
+        for row in range(boundries.rowStart+1, boundries.rowEnd-1):
+            self.markCellVisitedAddToSpiralPrint(matrix, row, boundries.colEnd-1, spiralPrint)
+        # print last row in reverse
+        for col in range(boundries.colEnd-1, boundries.colStart-1, -1):
+            self.markCellVisitedAddToSpiralPrint(matrix, boundries.rowEnd-1, col, spiralPrint)
+        # print first col
+        for row in range(boundries.rowEnd-2, boundries.rowStart, -1):
+            self.markCellVisitedAddToSpiralPrint(matrix, row, boundries.colStart, spiralPrint)
+        
+    def spiralOrder(self, matrix):
+        spiralPrint = []
+        boundryIndex = 0
+        boundries = self.setBoundries(matrix, boundryIndex)
+        # shirnk boundries until bounds are equal.
+        while(boundries.rowStart < boundries.rowEnd and boundries.colStart < boundries.colEnd):
+            boundryIndex = boundryIndex + 1
+            self.printSpiral(matrix, boundries, spiralPrint)
+            boundries = self.setBoundries(matrix, boundryIndex)
+        return spiralPrint
+        """
+        :type matrix: List[List[int]]
+        :rtype: List[int]
+        """
+        
diff --git a/Blind 75/README.md b/Blind 75/README.md
@@ -1,6 +1,6 @@
 <h1>Blind 75</h1>
   <a href="https://leetcode.com/discuss/general-discussion/460599/blind-75-leetcode-questions">Leetcode link to the post.</a>
-  <h4>Total Completed: 25</h4>
+  <h4>Total Completed: 27</h4>
   <h2>Array</h2>
     <ul>
       <li><a href="Programs/Two Sum.py">Two Sum</a> 
@@ -201,7 +201,12 @@
           This ensures we use no extra space and do it in O(n) time.
         </p>
       </li>
-      <li>Spiral Matrix</li>
+      <li><a href="Programs/Spiral Matrix.py">Spiral Matrix</a> 
+        <p><b>Approach</b>: Had to see this idea from leetcode solutions. <br/>
+          First write a function that first prints the spiral of rows and cols, then just reduce the bounds and do the same. <br/>
+          Don't forget the mark the cells visited to avoid duplicates.
+        </p>
+      </li>
       <li>Rotate Image</li>
       <li>Word Search</li>
     </ul>
