fix: wrong answer of find_common_string
#1817
| Job | Run time |
|---|---|
| 30s | |
| 46s | |
| 34s | |
| 42s | |
| 33s | |
| 3m 5s |
find_common_string
#1817
| Job | Run time |
|---|---|
| 30s | |
| 46s | |
| 34s | |
| 42s | |
| 33s | |
| 3m 5s |