In a string S of lowercase letters, these letters form consecutive groups of the same character.
For example, a string like S = "abbxxxxzyy" has the groups "a", "bb", "xxxx", "z" and "yy".
Call a group large if it has 3 or more characters. We would like the starting and ending positions of every large group.
The final answer should be in lexicographic order.
Example 1:
Input: "abbxxxxzzy"
Output: [[3,6]]
Explanation: "xxxx" is the single large group with starting 3 and ending positions 6.
Example 2:
Input: "abc"
Output: []
Explanation: We have "a","b" and "c" but no large group.
Example 3:
Input: "abcdddeeeeaabbbcd"
Output: [[3,5],[6,9],[12,14]]
Note: 1 <= S.length <= 1000
Accepted
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Submissions
37,752
class Solution:
def largeGroupPositions(self, S):
"""
:type S: str
:rtype: List[List[int]]
"""
res = []
i,j = 0,0
while j<len(S):
while j<len(S) and S[j]==S[i]:
j += 1
if j-i>=3:
res.append([i,j-1])
i = j
return res