jump_game_4.py

from collections import defaultdict

def solve(arr):
    d, t = defaultdict(list), len(arr) - 1
        
    for i, n in enumerate(arr):
        d[n] += i,
            
    q, seen = [(0, 0)], defaultdict(lambda:'inf')
        
    for i, h in q:
        if i == t: return h
        for j in [i+1, i-1, *d[arr[i]]]:
            if i != j and 0 <= j <= t and seen[j] > h+1:
                seen[j] = h+1
                q += (j, h+1),
            
        d.pop(arr[i])