Buggy python submission (verdict: Time Limit Exceeded):
import numpy as np

def main():
    n, k = map(int, input().split())
    a = list(map(lambda x: int(x)-1, input().split()))
    count = 0
    foot = [0]
    is_loop = False

    for i in range(1,k):
        foot.append(a[foot[-1]])
        if foot.count(foot[-1]) == 2:
            st_i = foot.index(foot[-1])
            lo_size = len(foot)-1 - st_i

            k -= st_i
            k %= lo_size
            
            print(foot[st_i+k]+1)
            is_loop = True
            break
    
    if not is_loop:
        print(a[foot[-1]]+1)


if __name__ == '__main__':
    main()


Fixed submission:
import numpy as np

def main():
    n, k = map(int, input().split())
    a = list(map(lambda x: int(x)-1, input().split()))
    foot = [0]
    is_loop = False
    ed = np.zeros([n], dtype=int)
    ed[0] = 1

    for i in range(1,k):
        go = a[foot[-1]]
        foot.append(go)
        if ed[go] == 1:
            st_i = foot.index(foot[-1])
            lo_size = len(foot)-1 - st_i

            k -= st_i
            k %= lo_size
            
            print(foot[st_i+k]+1)
            is_loop = True
            break
        ed[go] = 1
    
    if not is_loop:
        print(a[foot[-1]]+1)


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import numpy as np

def main():
    n, k = map(int, input().split())
    a = list(map(lambda x: int(x)-1, input().split()))
    count = 0
    foot = [0]
    is_loop = False

    for i in range(1,k):
        foot.append(a[foot[-1]])
        if foot.count(foot[-1]) == 2:
            st_i = foot.index(foot[-1], 0, len(foot)-1)
            lo_size = len(foot)-1 - st_i

            k -= st_i
            k %= lo_size
            
            print(foot[st_i+k]+1)
            is_loop = True
            break
    
    if not is_loop:
        print(a[foot[-1]]+1)


if __name__ == '__main__':
    main()


Fixed submission:
import numpy as np

def main():
    n, k = map(int, input().split())
    a = list(map(lambda x: int(x)-1, input().split()))
    foot = [0]
    is_loop = False
    ed = np.zeros([n], dtype=int)
    ed[0] = 1

    for i in range(1,k):
        go = a[foot[-1]]
        foot.append(go)
        if ed[go] == 1:
            st_i = foot.index(foot[-1])
            lo_size = len(foot)-1 - st_i

            k -= st_i
            k %= lo_size
            
            print(foot[st_i+k]+1)
            is_loop = True
            break
        ed[go] = 1
    
    if not is_loop:
        print(a[foot[-1]]+1)


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Runtime Error):
import numpy as np

def main():
    n, k = map(int, input().split())
    a = list(map(lambda x: int(x)-1, input().split()))
    count = 0
    foot = [None]*2*10**5
    foot[0] = 0
    is_loop = False

    for i in range(1,k):
        foot[i] = a[foot[i-1]]
        if foot.count(foot[i]) == 2:
            st_i = foot.index(foot[i], 0, i)
            lo_size = i - st_i
            loop = foot[st_i:i]

            k -= st_i
            k %= lo_size
            
            print(loop[k]+1)
            is_loop = True
            break
    
    if not is_loop:
        print(foot[k]+1)

if __name__ == '__main__':
    main()

Fixed submission:
import numpy as np

def main():
    n, k = map(int, input().split())
    a = list(map(lambda x: int(x)-1, input().split()))
    foot = [0]
    is_loop = False
    ed = np.zeros([n], dtype=int)
    ed[0] = 1

    for i in range(1,k):
        go = a[foot[-1]]
        foot.append(go)
        if ed[go] == 1:
            st_i = foot.index(foot[-1])
            lo_size = len(foot)-1 - st_i

            k -= st_i
            k %= lo_size
            
            print(foot[st_i+k]+1)
            is_loop = True
            break
        ed[go] = 1
    
    if not is_loop:
        print(a[foot[-1]]+1)


if __name__ == '__main__':
    main()