原题题目
代码实现(首刷自解)
class Solution {
public:int countHomogenous(string s) {
int mod = 1000000007,ret = 0;char temp = s[0];long count = 1;for(int i=0;i<s.size();++i){
if(i && temp == s[i]) ++count;if(i == s.size()-1 || temp != s[i]){
ret = (ret + ((count+1)*(count))/2) % mod;if(temp != s[i] && i == s.size()-1) ++ret;count = 1;temp = s[i];}}return ret;}
};