830. Positions of Large Groups
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
在小写字母的字符串S中，这些字母形成相同字符的连续组。
例如，诸如S =“abbxxxxzyy”的字符串具有组“a”，“bb”，“xxxx”，“z”和“yy”。
如果一个组有3个或更多字符，则调用它。我们想要每个大集团的起点和终点。
最终答案应该是字典顺序。
public class PositionsOfLargeGroups {
public List<List<Integer>> largeGroupPositions(String S) {
List<List<Integer>> res = new ArrayList<>();
char temp = S.toCharArray()[0];
int count = 0;
int start = 0;
int end = 0;
for (int i = 0; i < S.length(); i++) {
List<Integer> list = new ArrayList<>();
if (temp == S.toCharArray()[i]) {
count++;
} else {
if (count >= 3) {
end = i - 1;
list.add(start);
list.add(end);
res.add(list);
}
start = i;
temp = S.toCharArray()[i];
count = 1;
}
if (i == S.length() - 1) {
if (count >= 3){
end = i;
list.add(start);
list.add(end);
res.add(list);
}
}
}
return res;
}
public static void main(String[] args) {
PositionsOfLargeGroups positionsOfLargeGroups = new PositionsOfLargeGroups();
positionsOfLargeGroups.largeGroupPositions("aaaaaaaabbb");
}
}
ac时间很长啊，逻辑思路要换换
