# 3. 神奇口袋 # dfs解决 深度优先遍历 maxn = 21 a = [0] * 21 vis = [0] * 21 global res def dfs(now, j): global res for i in range(j, n): cal = now + a[i] if cal > 40: dfs(now, i + 1) elif cal < 40: dfs(cal, i + 1) else: res += 1 ...