Dota2 Senate Python Solution with Tests

lcpy gen -n 649   # by problem number
lcpy gen -s dota2_senate   # by problem name

Input: senate = "RD"
Output: "Radiant"
Explanation: The first senator (Radiant) bans the next senator's right in round 1. In round 2, the first senator announces victory.

Input: senate = "RDD"
Output: "Dire"
Explanation: The first senator (Radiant) bans the second senator's right. The third senator (Dire) bans the first senator's right. In round 2, the third senator announces victory.

from collections import deque


class Solution:
    # Time: O(n) each senator is banned at most once
    # Space: O(n) for the queues
    def predict_party_victory(self, senate: str) -> str:
        n = len(senate)
        radiant: deque[int] = deque(i for i, ch in enumerate(senate) if ch == "R")
        dire: deque[int] = deque(i for i, ch in enumerate(senate) if ch == "D")

        while radiant and dire:
            r = radiant.popleft()
            d = dire.popleft()
            # Earlier senator bans the other; winner re-enters with a future index.
            if r < d:
                radiant.append(r + n)
            else:
                dire.append(d + n)

        return "Radiant" if radiant else "Dire"