The downsides of ‘proteinmaxxing’
Easy (call stack is meaningful)
，详情可参考服务器推荐
Members of the Big Ten Conference in 2025-26 include Illinois, Indiana, Iowa, Maryland, Michigan, Michigan State, Minnesota, Nebraska, Northwestern, Ohio State, Oregon, Penn State, Purdue, Rutgers, UCLA, USC, and Wisconsin.
// 核心过滤：弹出栈中「≤当前元素」的数（易错点2：必须是≤，不是<）