2024-07-26P3131 [USACO16JAN] Subsequences Summing to Sevens S传送锚点:[USACO16JAN]SubsequencesSummingtoSevensS-洛谷题目描述FarmerJohn's\(N\)cowsarestandinginarow,astheyhaveatendencytodofromtimetotime.EachcowislabeledwithadistinctintegerIDnumbersoFJcantellthemapart.FJwould