File size: 5,026 Bytes
5d5048e
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
import OAI.Combinatorics.LowSpaceSubsetSum.Search.BudgetedPrefixController
import OAI.Combinatorics.LowSpaceSubsetSum.Separators.BudgetedSeparatorFlow

namespace OAI

namespace LowSpaceSubsetSum.BudgetedPrefixController

open BudgetedSeparatorFlow (Account)
variable {n : ℕ} {I : Instance n} {C : ℕ}

private theorem force_bound (P : StoredRestriction n) (i : Fin n) :
    (P.force i false).2 + (P.force i true).2 + 8 ≤ StoredPrefixController.header n := by
  have h₀ := P.force_work i false
  have h₁ := P.force_work i true
  unfold StoredPrefixController.header
  omega

theorem run_account
    (collect : StoredRestriction n → ℕ → Option (StoredEntry.Dictionary I C × ℕ) × ℕ)
    (check : Array (StoredEntry n) → ℕ → Option (Bool × ℕ) × ℕ)
    (hc : ∀ P b, Account b (collect P b)) (hk : ∀ a b, Account b (check a b))
    (order : List (Fin n)) (P : StoredRestriction n) (budget : ℕ) :
    Account budget (run collect check order P budget) := by
  have hh : 8 ≤ StoredPrefixController.header n := by unfold StoredPrefixController.header; omega
  induction order generalizing P budget with
  | nil =>
    rw [run]
    split
    next hb =>
      generalize htdef : collect P (budget - StoredPrefixController.header n) = task
      have htask := hc P (budget - StoredPrefixController.header n)
      rw [htdef] at htask
      cases ht : task.1 with
      | none =>
        simp only [ht, BudgetedSeparatorFlow.Account]
        constructor
        · exact le_trans (Nat.add_le_add_right htask.1 2) (by omega)
        · intro v left h
          contradiction
      | some p =>
        rcases p with ⟨d, left⟩
        have hts := htask.2 d left ht
        simp only [ht, BudgetedSeparatorFlow.Account]
        split
        · constructor
          · dsimp only; omega
          · intro v rest h
            cases h
            dsimp only
            omega
        · have hchecked := hk d.val.records left
          have hw := hchecked.1
          constructor
          · change task.2 + (check d.val.records left).2 + 4 ≤ _
            omega
          · intro v rest h
            have hs := hchecked.2 v rest h
            change rest ≤ budget ∧ task.2 + (check d.val.records left).2 + 4 ≤ budget - rest
            omega
    next _ =>
      constructor
      · dsimp only; omega
      · intro v left h
        contradiction
  | cons i order ih =>
    rw [run]
    split
    next hb =>
      generalize htdef : collect P (budget - StoredPrefixController.header n) = task
      have htask := hc P (budget - StoredPrefixController.header n)
      rw [htdef] at htask
      cases ht : task.1 with
      | none =>
        simp only [ht, BudgetedSeparatorFlow.Account]
        constructor
        · exact le_trans (Nat.add_le_add_right htask.1 2) (by omega)
        · intro v left h
          contradiction
      | some p =>
        rcases p with ⟨d, available⟩
        have hts := htask.2 d available ht
        simp only [ht, BudgetedSeparatorFlow.Account]
        split
        · have hf := force_bound P i
          generalize hldef : run collect check order (P.force i false).1 available = left
          have hl := ih (P.force i false).1 available
          rw [hldef] at hl
          have hlw := hl.1
          cases he : left.1 with
          | none =>
            constructor
            · change task.2 + (P.force i false).2 + left.2 + 6 ≤ _
              omega
            · intro v rest h
              contradiction
          | some p =>
            rcases p with ⟨v, rest⟩
            have hls := hl.2 v rest he
            cases v
            · dsimp only
              generalize hrdef : run collect check order (P.force i true).1 rest = right
              have hr := ih (P.force i true).1 rest
              rw [hrdef] at hr
              have hrw := hr.1
              constructor
              · omega
              · intro v remaining h
                have hrs := hr.2 v remaining h
                change remaining ≤ budget ∧
                  task.2 + (P.force i false).2 + left.2 + (P.force i true).2 + right.2 + 8 ≤ budget - remaining
                omega
            · constructor
              · change task.2 + (P.force i false).2 + left.2 + 6 ≤ _
                omega
              · intro v remaining h
                cases h
                change rest ≤ budget ∧ task.2 + (P.force i false).2 + left.2 + 6 ≤ budget - rest
                omega
        · have hchecked := hk d.val.records available
          have hw := hchecked.1
          constructor
          · change task.2 + (check d.val.records available).2 + 4 ≤ _
            omega
          · intro v rest h
            have hs := hchecked.2 v rest h
            change rest ≤ budget ∧ task.2 + (check d.val.records available).2 + 4 ≤ budget - rest
            omega
    next _ =>
      constructor
      · dsimp only; omega
      · intro v left h
        contradiction

end LowSpaceSubsetSum.BudgetedPrefixController

end OAI