HackerRank World Codesprint April: Jumping on the Clouds
solution
Simulate it greedily. $O(N)$.
If you can jump to $i+2$-th cloud, then do it, else jump to $i+1$-th one.
implementation
#!/usr/bin/env python3
n = int(input())
a = list(map(int,input().split()))
ans = 0
i = 0
while i < n-1:
i = min(i+2, n-1)
if a[i] == 1:
i -= 1
ans += 1
print(ans)