Use all positions to determine order

Since we expect very few votes there is a high probability that several
candidates will be not be ranked first by anybody. Which one is
eliminated is essentially random, so it could happen that a candidate
which is ranked second by everybody (and therefore would probably be the
winner) is eliminated in the first round and never considered again.
To prevent this, we sort by all ranks in order. So among those with the
same number of first ranks the one with the most second ranks wins, if
those are also the same we use the third rank etc. This should ensure
that each round really eliminates the worst candidate (ties are still
possible, but only if the votes at all ranks are the same - in which
case no objective distinction is left and random choice is acceptable).

app.py

@@ -303,11 +303,11 @@ def runoff(ballots):
     candidates = {}
     for ballot in ballots:
         for r in ballot:
-            count[r.id] = 0
+            count[r.id] = [0] * len(ballot)
             candidates[r.id] = r
     for ballot in ballots:
-        # The votes are sorted by position, so the first entry is the favourite
-        count[ballot[0].id] += 1
+        for pos, r in enumerate(ballot):
+            count[r.id][pos] += 1
     result = sorted(count.keys(), key=lambda i: count[i])
     log.debug("result of this round:")
     for r in result:

utils/instantrunoff

@@ -48,11 +48,11 @@ def runoff(ballots):
     candidates = {}
     for ballot in ballots:
         for r in ballot:
-            count[r.id] = 0
+            count[r.id] = [0] * len(ballot)
             candidates[r.id] = r
     for ballot in ballots:
-        # The votes are sorted by position, so the first entry is the favourite
-        count[ballot[0].id] += 1
+        for pos, r in enumerate(ballot):
+            count[r.id][pos] += 1
     result = sorted(count.keys(), key=lambda i: count[i])
     print("result of this round:")
     for r in result: