SEATTLE — The solution is cheap and simple: As cities see their homeless populations grow, many are buying one-way bus tickets to send people to a more promising destination, where family or friends can help get them back on their feet. San Francisco’s “Homeward Bound” program, started more than a decade ago when Gov. Gavin Newsom of California was the city’s mayor, transports hundreds of people a year. Smaller cities around the country — Myrtle Beach, S.C., and Medford, Ore., among them — have recently committed funding to the idea. Sign Up For the Morning Briefing Newsletter And in Seattle...