Let = minimum cost to reach tree . Base: (start here, no cost). Transition: . Naive: . For each , try all .
But look at the transition: . For fixed , rewrite as . This is where , , . That's CHT form!
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##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
State and transition
Let = minimum cost to reach tree . Base: (start here, no cost). Transition: . Naive: . For each , try all .
But look at the transition: . For fixed , rewrite as . This is where , , . That's CHT form!