day 5 cleanup

day05/sol2.py

@@ -9,32 +9,31 @@ def read_map(input):
 
 
 def overlap(a,b, x,y):
-    """ if two ranges a..a+b and x..x+y overlap, returns the overlapping range"""
+    """ if two ranges a..b and x..y overlap, returns the overlapping range"""
     if b <= x or y <= a:
         return (0,0) # no overlap
     return max(a,x), min(b,y)
 
 def lookup(map, m,n):
-    r = []
-    used = []
+    r = [] # (start,count)
+    used = [] # (start,end)
     for dst, src, count in map:
         a,b = overlap(m,m+n, src,src+count)
         if a != b:
             assert a < b
             used.append((a,b))
             r.append((a-src+dst,b-a))
-    if not used:
-        r.append((m,n))
-    else:
-        used.sort()
-        end = m+n
-        for a,b in used:
-            assert m <= a
-            if m < a:
-                r.append((m, a-m))
-            m = b
-        if m < end:
-            r.append((m,end-m))
+    # unused values translate to themselves
+    used.sort()
+    end = m+n
+    for a,b in used:
+        assert m <= a
+        if m < a:
+            r.append((m, a-m))
+        m = b
+    if m < end:
+        r.append((m,end-m))
+    #r.sort()
     return r
 
 def nums(s):
@@ -60,17 +59,22 @@ def read_puzzle(input):
     print(seeds)
     print(maps)
 
-    locs = []
+    return seeds,maps
+
+def solve(data):
+    seeds, maps = data
+
     for i in range(0, len(seeds), 2):
         m,n = seeds[i:i+2]
-        print(n, lookup(maps[('seed','soil')], m,n), seed2loc(maps, m,n))
-        locs.extend(seed2loc(maps, m,n))
+        print(n, lookup(maps[('seed','soil')], m,n))
+
+    ranges = [(seeds[i],seeds[i+1]) for i in range(0,len(seeds),2)]
+    locs = seed2loc(maps, ranges)
 
     print(min(locs))
 
 
-def seed2loc(maps, m,n):
-    r = [(m,n)]
+def seed2loc(maps, r):
     for a,b in [
         ('seed', 'soil'),
         ('soil', 'fertilizer'),
@@ -89,4 +93,5 @@ def seed2loc(maps, m,n):
     return r
 
 import sys
-read_puzzle(sys.stdin)
+p = read_puzzle(sys.stdin)
+solve(p)