【360笔试】散步

第一题太简单，不贴了。
但是这种秋招笔试，样例库的样例不多，笔试能过，不代表算法正确，欢迎网友提bug~
题目盗图

import sys
direc = [-1, 1]
line = sys.stdin.readline().strip()
n, m = list(map(int, line.split()))
num = 0
p, q = [], []

def judge(a):    
    if(a > 0 and a < n + 1):
        return True
    return False

def dfs(cur, id_):
    if(id_ >= m):        
        if(cur <= n and cur > 0):
            q.append(cur)            
        return
    for k in range(2):
        new = cur + p[id_] * direc[k]
        if(judge(new) == True):
            dfs(new, id_ + 1)
            cur = new - p[id_] * direc[k]
    return 
for i in range(m):
    p.append(int(sys.stdin.readline().strip()))
for st in range(1, n+1):
    dfs(st, 0)    
print(len(list(set(q))))