题意
做法
将每个点(2k+2)个点,成行排列:
(x_1,x_2,x_3,cdots,x_{2k+1},x_{2k+2}),(Slongrightarrow x_1(flow:infty),x_{2k+2}longrightarrow T(flow:infty))
(x_1longrightarrow x_2(flow:F(k)),x_2longrightarrow x_3(flow:F(k-1)),cdots,x_{2k+1}longrightarrow x_{2k+2}(flow:F(-k)))
(F(k))表示选(k)在((i,j))上付出的初始成本
对于相邻的两个点:((i,j,l)--(i',j',l)(flow:1)),求最小割,当相邻两点选择((l_1,l_2)),会割掉(|l_1-l_2|)