leetcode-830-Positions of Large Groups
题目描述:
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
要完成的函数:
vector<vector<int>> largeGroupPositions(string S)
说明:
1、给定一个字符串S,如果一个字符连续出现三次及三次以上,那么它就是一个“大组合”,要求找出所有“大组合”的起始位置和结束位置,最终以vector<vector<int>>的形式返回。
2、明白题意,这又是一道简单题。
直接贴上代码(附详解),如下:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | vector<vector< int >> largeGroupPositions(string S) { int s1=S.size(),i=0,j; vector<vector< int >>res; //最后返回的vector vector< int >res1; //子vector while (i<s1-2) { if (S[i]==S[i+1]&&S[i]==S[i+2]) //如果满足条件 { res1.clear(); //清空res1 res1.push_back(i); //插入起始位置到res1 j=i+3; while (j<s1) //找到不等于S[i]的字符位置 { if (S[i]==S[j]) j++; else break ; } res1.push_back(j-1); //插入结束位置到res1 res.push_back(res1); //res1插入到res里面 i=j; //更新i的值 } else i++; } return res; } |
上述代码实测13ms,因为服务器接收到的cpp submissions有限,所以没有打败的百分比。
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