1561B - Charmed by the Game - CodeForces Solution

import sys
from sys import stdout

input = sys.stdin.readline
inf = float('inf')


def getInt():
    return int(input())


def getStr():
    return input().strip()


def getList(split=True):
    s = getStr()
    if split:
        s = s.split()
    return list(map(int, s))



t = getInt()


def solve():
    a, b = getList()
    n = a+b
    res = set()
    for hold in {n >> 1, n+1 >> 1}:
        for Break in range(min(n-hold, a)+1):
            if 0 <= hold - a + Break <= b:
                res.add(2*Break+hold-a)
    print(len(res))
    print(*sorted(res))


for _ in range(t):
    solve()