non_neg_int_wo_consec_one.py (915B)
| # 600. Non-negative Integers without Consecutive Ones
"""
given a positive integer 'n', return the number of the integers in the range
'[0, n]' whose binary representations do not contain consecutive ones.
"""
class Solution(object):
def findIntegers(self, n):
"""
:type n: int
:rtype: int
"""
s = bin(n + 1)[2:]
num = len(s)
dp = [1, 2] + [0] * (num - 2)
for i in range(2, num):
dp[i] = dp[i - 1] + dp[i - 2]
flag, ans = False, 0
for i in range(num):
if s[i] == "0":
continue
if flag:
break
if i > 0 and s[i - 1] == "1":
flag = True
ans += dp[-i - 1]
return ans
if __name__ == "__main__":
obj = Solution()
print(obj.findIntegers(n=5))
print(obj.findIntegers(n=1))
print(obj.findIntegers(n=2))
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