题目:原题链接(中等)
标签:数组、哈希表
解法 | 时间复杂度 | 空间复杂度 | 执行用时 |
Ans 1 (Python) | O ( 12 1 2 + N ) | O ( 121 ) | 200ms (41.03%) |
Ans 2 (Python) | |||
Ans 3 (Python) |
解法一:
class Solution:
def numFriendRequests(self, ages: List[int]) -> int:
count = [0] * 121
for age in ages:
count[age] += 1
ans = 0
for age1, n1 in enumerate(count):
for age2, n2 in enumerate(count):
if age1 * 0.5 + 7 >= age2:
continue
if age1 < age2:
continue
if age1 < 100 < age2:
continue
if age1 == age2:
ans += n1 * (n1 - 1)
else:
ans += n1 * n2
return ans