Spiral Matrix medium

Author: weiy

Diff for: Array/SpiralMatrix.py

@@ -0,0 +1,134 @@
+"""
+Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.
+
+Example 1:
+
+Input:
+[
+ [ 1, 2, 3 ],
+ [ 4, 5, 6 ],
+ [ 7, 8, 9 ]
+]
+Output: [1,2,3,6,9,8,7,4,5]
+Example 2:
+
+Input:
+[
+  [1, 2, 3, 4],
+  [5, 6, 7, 8],
+  [9,10,11,12]
+]
+Output: [1,2,3,4,8,12,11,10,9,5,6,7]
+
+
+思路：
+
+0, 0开始走，
+right -> down,
+down -> left,
+left -> up,
+up -> right.
+每走过一点，将值添加到结果中，走过的点记为 'x'。当四周都是 'x' 或边界时结束。
+
+测试地址：
+https://leetcode.com/problems/spiral-matrix/description/
+
+beat 99.10%.
+
+"""
+def checkStop(matrix, x, y):
+    t = [(x+1, y),
+         (x-1, y),
+         (x, y+1),
+         (x, y-1),
+         (x, y)]
+    for i in t:
+        try:
+            if i[1] < 0 or i[0] < 0:
+                continue
+                
+            if matrix[i[1]][i[0]] != 'x':
+                return False
+        except IndexError:
+            continue
+    else:
+        return True
+    
+    
+class Solution(object):
+    def right(self, matrix, x, y, result, stop):
+        if checkStop(matrix, x, y):
+            return result
+        while 1:
+            try:
+                # matrix
+                if matrix[y][x] == 'x':
+                    raise IndexError
+                result.append(matrix[y][x])
+                matrix[y][x] = 'x'
+                x += 1
+
+            except IndexError:
+                x -= 1
+                return self.down(matrix, x, y+1, result, stop)
+    
+    def down(self, matrix, x ,y, result, stop):
+        if checkStop(matrix, x, y):
+            return result
+        while 1:
+            try:
+                # matrix
+                if matrix[y][x] == 'x':
+                    raise IndexError
+                result.append(matrix[y][x])
+                matrix[y][x] = 'x'
+                y += 1
+            except IndexError:
+                y -= 1
+                return self.left(matrix, x-1, y, result, stop)
+    
+    def left(self, matrix, x, y, result, stop):
+        if checkStop(matrix, x, y):
+            return result
+        while 1:
+            try:
+                # matrix
+                if matrix[y][x] == 'x' or x < 0:
+                    raise IndexError
+                result.append(matrix[y][x])
+                matrix[y][x] = 'x'
+                x -= 1
+            except IndexError:
+                x += 1
+                return self.up(matrix, x, y-1, result, stop)        
+    
+    def up(self, matrix, x, y, result, stop):
+        if checkStop(matrix, x, y):
+            return result
+
+        while 1:
+            try:
+                # matrix
+                if matrix[y][x] == 'x' or y < 0:
+                    raise IndexError
+                result.append(matrix[y][x])
+                matrix[y][x] = 'x'
+                y -= 1
+            except IndexError:
+                y += 1
+                return self.right(matrix, x+1, y, result, stop)             
+    
+    def spiralOrder(self, matrix):
+        """
+        :type matrix: List[List[int]]
+        :rtype: List[int]
+        """
+        x, y = 0, 0
+        
+        result = []
+        # right -> down
+        # down -> left
+        # left -> up
+        # up -> right
+        stop = {}
+        return self.right(matrix, 0, 0, result, stop)