朴素
f[i][j] = max(f[i - 1][j], f[i - 1][j - v] + w, f[i - 1][j - 2v] + 2w, ...)
f[i][j - v] = max(f[i - 1][j - v], f[i - 1][j - 2v] + w, ...)
=>
f[i][j] = max(f[i - 1][j],f[i][j - v] + w)
优化
f[j] = max(f[j], f[j - v] + w)
标签：...,2v,背包,公式,算法,max From： https://www.cnblogs.com/tnxts/p/16825491.html