title
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]]
solution
统计连续最长字符的start, end
static int Static_X = [](){
std::ios::sync_with_stdio(false);
cin.tie(NULL);
return 0;
}();
class Solution {
public:
vector<vector<int>> largeGroupPositions(string S) {
string s = S+'#';
vector<vector<int>> res;
int count = 1;
int start = 0, end = 0;
for (int i = 0; i < s.length()-1; i++) {
if (s[i] == s[i + 1]) {
if (count == 1)
start = i;
count++;
}
else {
if (count >= 3) {
res.push_back({ start,i });
}
count = 1;
}
}
return res;
}
};