题目
Given an array of integers arr, and three integers a, b and c. You need to find the number of good triplets.
A triplet (arr[i], arr[j], arr[k]) is good if the following conditions are true:
- 0 <= i < j < k < arr.length
-
arr[i] - arr[j] <= a -
arr[j] - arr[k] <= b -
arr[i] - arr[k] <= c Where x denotes the absolute value of x.
Return the number of good triplets.
解题思路
遍历ijk，判断是否符合条件
代码
class Solution:
def countGoodTriplets(self, arr: List[int], a: int, b: int, c: int) -> int:
res = 0
n = len(arr)
for i in range(n - 2):
for j in range(i + 1, n - 1):
if math.fabs(arr[j] - arr[i]) > a:
continue
for k in range(j + 1, n):
if math.fabs(arr[k]-arr[i]) <= c or math.fabs(arr[k] - arr[j]) <= b:
res += 1
return res
