all tasks

Task/Spiral-matrix/Python/spiral-matrix-1.py

@@ -0,0 +1,22 @@
+def spiral(n):
+    dx,dy = 1,0            # Starting increments
+    x,y = 0,0              # Starting location
+    myarray = [[None]* n for j in range(n)]
+    for i in xrange(n**2):
+        myarray[x][y] = i
+        nx,ny = x+dx, y+dy
+        if 0<=nx<n and 0<=ny<n and myarray[nx][ny] == None:
+            x,y = nx,ny
+        else:
+            dx,dy = -dy,dx
+            x,y = x+dx, y+dy
+    return myarray
+
+def printspiral(myarray):
+    n = range(len(myarray))
+    for y in n:
+        for x in n:
+            print "%2i" % myarray[x][y],
+        print
+
+printspiral(spiral(5))

Task/Spiral-matrix/Python/spiral-matrix-2.py

@@ -0,0 +1,23 @@
+def spiral(n):
+    def spiral_part(x, y, n):
+        if x == -1 and y == 0:
+            return -1
+        if y == (x+1) and x < (n // 2):
+            return spiral_part(x-1, y-1, n-1) + 4*(n-y)
+        if x < (n-y) and y <= x:
+            return spiral_part(y-1, y, n) + (x-y) + 1
+        if x >= (n-y) and y <= x:
+            return spiral_part(x, y-1, n) + 1
+        if x >= (n-y) and y > x:
+            return spiral_part(x+1, y, n) + 1
+        if x < (n-y) and y > x:
+            return spiral_part(x, y-1, n) - 1
+
+    array = [[0] * n for j in xrange(n)]
+    for x in xrange(n):
+        for y in xrange(n):
+            array[x][y] = spiral_part(y, x, n)
+    return array
+
+for row in spiral(5):
+    print " ".join("%2s" % x for x in row)

Task/Spiral-matrix/Python/spiral-matrix-3.py

@@ -0,0 +1,16 @@
+def spiral(n):
+    dat = [[None] * n for i in range(n)]
+    le = [[i + 1, i + 1] for i in reversed(range(n))]
+    le = sum(le, [])[1:]  # for n = 5 le will be [5, 4, 4, 3, 3, 2, 2, 1, 1]
+    dxdy = [[1, 0], [0, 1], [-1, 0], [0, -1]] * ((len(le) + 4) / 4)  # long enough
+    x, y, val = -1, 0, -1
+    for steps, (dx, dy) in zip(le, dxdy):
+        x, y, val = x + dx, y + dy, val + 1
+        for j in range(steps):
+            dat[y][x] = val
+            if j != steps-1:
+                x, y, val = x + dx, y + dy, val + 1
+    return dat
+
+for row in spiral(5): # calc spiral and print it
+    print ' '.join('%3s' % x for x in row)

Task/Spiral-matrix/Python/spiral-matrix-4.py

@@ -0,0 +1,19 @@
+import itertools
+
+concat = itertools.chain.from_iterable
+def partial_sums(items):
+    s = 0
+    for x in items:
+        s += x
+        yield s
+
+grade = lambda xs: sorted(range(len(xs)), key=xs.__getitem__)
+values = lambda n: itertools.cycle([1,n,-1,-n])
+counts = lambda n: concat([i,i-1] for i in range(n,0,-1))
+reshape = lambda n, xs: zip(*([iter(xs)] * n))
+
+spiral = lambda n: reshape(n, grade(list(partial_sums(concat(
+                       [v]*c for c,v in zip(counts(n), values(n)))))))
+
+for row in spiral(5):
+    print(' '.join('%3s' % x for x in row))