数组移动跳跃

def out_of(data):  #用visit数组记录已访问过的下标
    index, step = 0, data[0]
    visit = [0] * len(data)
    visit[0] = 1
    while True:
        index += step
        if index >= len(data) or index < 0:
            return True
        if visit[index]:
            return False
        step = data[index]
        visit[index] = 1

data = list(map(int, input()[1:-1].split(',')))
print('true' if out_of(data) else 'false')

arr = list(map(int, input().strip()[1: -1].split(',')))

index = 0
temp = []
try:
    while index not in temp:
        temp.append(index)
        index += arr[index]
    print('false')
except IndexError:
    print('true')

arr = input() if len(arr)<=4: if '0' in arr: print('false') else: print('true') else:
    numbers = list(map(str, arr.split(',')))
    numbers[0] = numbers[0][1:]
    numbers[-1] = numbers[-1][:-1]
    numbers = list(map(int, numbers))
    visited = []
    index = 0  while index>=0 and index<len(numbers): if index not in visited:
            visited.append(index)
            index+=numbers[index] continue  else: print('false') break  if index<0 or index>=len(numbers): print('true')

s = input()
s = s[1:len(s)-1]
a = list(map(int,s.split(',')))
i = 0
while i < len(a) and i >= 0:
    i += a[i]
    if (i == len(a) - 1) and (i + a[i] < len(a) and i + a[i] >= 0):
        print('false')
        break
if i >= len(a) or i < 0:
    print('true')

""""
考察条件判断
"""

if __name__ == "__main__":
    a = eval(input().strip())
    ans = False
    t = 0
    while True:
        if t < 0 or t >= len(a):
            ans = True
            break
        if a[t] == 0:
            ans = False
            break
        temp = t + a[t]
        a[t] = 0
        t = temp
    print("true" if ans else "false")