Module 14: Find Spans in the Grid (Python code)

a.py

@@ -1,3 +1,5 @@
+from copy import copy
+
 def ToUpper(s):
     return s.upper()
 
@@ -14,7 +16,10 @@ class Point:
 
 ## ----------------------------------------------------------------------------
 ##-Span
-class Span:
+class Spans:
+
+    spans = []
+
     def __init__(self, p, l, v):
         self.point = p
         self.len = l
@@ -103,6 +108,7 @@ class Grid:
     def __init__(self, n):
         self.name = n
         self.lines = []
+        self.sp = Spans.spans
 
     def rows(self):
         return len(self.lines)
@@ -113,6 +119,63 @@ class Grid:
         else:
             return len(self.lines[0])
 
+    # Returns character value of the box at point 'p'
+    # 'p' must be in bounds
+    def box(self, p):
+        assert self.in_bounds(p), p
+        return self.lines[p.row][p.col]
+
+    # Returns True if the point p is a '.' "block" in the grid
+    # 'p' must be in bounds
+    def is_block(self, p):
+        return self.box(p) == '.'
+
+    def is_blank(self, p):
+        return self.box(p) == '-'
+
+    def is_letter(self, p):
+        c = self.box(p)
+        return c >= 'A' and c <= 'Z'
+
+    def in_bounds(self, p):
+        return p.row >= 0 and p.row < self.rows() and p.col >= 0 and p.col < self.cols()
+
+    # Next increments the point across the grid, one box at a time
+    # Returns True if point is still in bounds
+    def Next(self, p, vert):
+        if vert:
+            p.row += 1
+            if p.row >= self.rows():
+                p.row = 0
+                p.col += 1
+        else:
+            p.col += 1
+            if p.col >= self.cols():
+                p.col = 0
+                p.row += 1        
+        return self.in_bounds(p)
+
+    def FillSpans_(self, vert):
+        p = Point()
+        while (self.in_bounds(p)):
+            while (self.in_bounds(p) and self.is_block(p)):
+                self.Next(p, vert)
+            if not self.in_bounds(p):
+                return
+            startp = copy(p)
+            #print(f"SPAN START: {startp}")
+
+            len_ = 0
+            while (self.in_bounds(p) and not self.is_block(p)):
+                self.Next(p, vert)
+                len_ += 1
+            #print(f"END OF SPAN!!! len={len_}")
+            self.sp.append(Spans(startp, len_, vert))
+    
+    def FillSpans(self):
+        self.FillSpans_(vert=False)  # horiz
+        self.FillSpans_(vert=True)  # vert
+
     def LoadFromFile(self, filename):
         with open(filename, 'r') as f:
             for line in f:
@@ -131,6 +194,11 @@ class Grid:
         for s in self.lines:
             print(f"  {''.join(s)}")
 
+    def PrintSpans(self):
+        print(f"Spans:")
+        for span in self.sp:
+            print(f"  {span}")
+
 if __name__ == "__main__":
     lib = Library()
     lib.ReadFromFile("top_12000.txt")
@@ -139,15 +207,5 @@ if __name__ == "__main__":
     grid.LoadFromFile("test")
     grid.Check()
     grid.Print()
-
-    p1 = Point()
-    p2 = Point(2, 1)
-
-    print(f"Point1 is {p1}")
-    print(f"Point2 is {p2}")
-
-    s1 = Span(p1, 3, True)
-    s2 = Span(p2, 5, False)
-
-    print(f"Span1 is {s1}")
-    print(f"Span2 is {s2}")
+    grid.FillSpans()
+    grid.PrintSpans()