Preserving my solutions for foobar

python/foobar/two/zombit.py

@@ -0,0 +1,44 @@
+#!/usr/bin/env python
+
+samples = [ [[[1,3],[3,6]],5], [[[10,14],[4,18],[19,20],[19,20],[13,20]],16] ]
+
+def answer(intervals):
+    """Calculate the total number of units covered by the supplied collection of intervals"""
+    while True:
+        changed, intervals = iterate(intervals)
+        if not changed:
+            break
+
+    covered = 0
+    for interval in intervals:
+        covered += interval[1] - interval[0]
+
+    return covered
+
+def iterate(intervals):
+    ranges = [intervals.pop(0)]
+    changed = False
+    while (len(intervals)>0):
+        interval = intervals.pop()
+        merged = False
+        for i in range(0,len(ranges)):
+            if overlaps(interval,ranges[i]):
+                ranges[i] = merge(ranges[i],interval)
+                merged = True
+                changed = True
+        if not merged:
+            ranges.append(interval)
+    return changed, ranges
+
+def overlaps(a,b):
+    if (a[0]<b[1]) and (a[1]>b[0]):
+        return True
+    else:
+        return False
+
+def merge(a,b):
+    return [min(a[0],b[0]),max(a[1],b[1])]
+
+for sample in samples:
+    print answer(sample[0])
+    print sample[1]