Gotou Misaki manga
From Chibi Manga: Hanako, who's living in the dormitory for girls, will be in big trouble because the girls dormitory will be combined with boy's dormitory... But she can't accept that! --------- From Shoujo Sense: Hanako doesn't have much experience with boys, so when she finds out Bara High (and its adjoined dormitory too!) is becoming co-ed, she becomes excited. But the first boy she meets is the top student from the boy's school, Kakeru, who turns out to be not as nice as he seems, and declares that he will make Hanako share a room with him! How will Hanako deal with this mess?!
From Day of the River: No matter how hard or painful it is, I’ve once again, fallen for you… On the day of the junior high entrance ceremony, Hinagata Nazuna fell in love with a second year student, Ichikawa Nao. Unfortunately, her love was short-lived as she discovered that he already had a girlfriend, the basketball club manager. As time passes, Nazuna decides to let go of her unrequited love for him and aims to find a new love interest. However, on the first day of her high school entrance ceremony she unexpectedly comes face to face with the boy who broke her heart years ago….