upd

algorithms/labs/lab6/code/1.py

@@ -0,0 +1,29 @@
+def thief_knapsack(weights, values, M, K):
+    cap = M * K
+    n = len(weights)
+    dp = [0] * (cap + 1)
+    take = [[False] * (cap + 1) for _ in range(n)]
+    for i in range(n):
+        w = weights[i]
+        v = values[i]
+        for c in range(cap, w - 1, -1):
+            if dp[c - w] + v > dp[c]:
+                dp[c] = dp[c - w] + v
+                take[i][c] = True
+    c = cap
+    items = []
+    for i in range(n - 1, -1, -1):
+        if take[i][c]:
+            items.append(i)
+            c -= weights[i]
+    items.reverse()
+    return dp[cap], items
+
+
+if __name__ == "__main__":
+    weights = [2, 3, 4, 5, 9, 7, 3]
+    values = [3, 4, 5, 8, 10, 7, 6]
+    M = 2
+    K = 10
+    best, items = thief_knapsack(weights, values, M, K)
+    print(best, items)

algorithms/labs/lab6/code/2.py

@@ -0,0 +1,35 @@
+def matrix_chain_order(p):
+    n = len(p) - 1
+    m = [[0] * n for _ in range(n)]
+    s = [[0] * n for _ in range(n)]
+    for L in range(2, n + 1):
+        for i in range(n - L + 1):
+            j = i + L - 1
+            m[i][j] = 10**18
+            for k in range(i, j):
+                q = m[i][k] + m[k + 1][j] + p[i] * p[k + 1] * p[j + 1]
+                if q < m[i][j]:
+                    m[i][j] = q
+                    s[i][j] = k
+    return m, s
+
+
+def build_parenthesization(s, i, j, names):
+    if i == j:
+        return names[i]
+    k = s[i][j]
+    return (
+        "("
+        + build_parenthesization(s, i, k, names)
+        + build_parenthesization(s, k + 1, j, names)
+        + ")"
+    )
+
+
+if __name__ == "__main__":
+    p = [30, 35, 15, 5, 10, 20, 25]
+    names = ["A", "B", "C", "D", "E", "F"][: len(p) - 1]
+    m, s = matrix_chain_order(p)
+    expr = build_parenthesization(s, 0, len(p) - 2, names)
+    print(m[0][len(p) - 2])
+    print(expr)

algorithms/labs/lab6/code/3.py

@@ -0,0 +1,29 @@
+def longest_increasing_run(a):
+    if not a:
+        return 0, -1, -1
+    best_len = 1
+    best_l = 0
+    best_r = 0
+    cur_len = 1
+    cur_l = 0
+    for i in range(1, len(a)):
+        if a[i] > a[i - 1]:
+            cur_len += 1
+        else:
+            if cur_len > best_len:
+                best_len = cur_len
+                best_l = cur_l
+                best_r = i - 1
+            cur_len = 1
+            cur_l = i
+    if cur_len > best_len:
+        best_len = cur_len
+        best_l = cur_l
+        best_r = len(a) - 1
+    return best_len, best_l, best_r
+
+
+if __name__ == "__main__":
+    a = [1, 2, 3, -1, 0, 1, 1, 2, 3, 4, -5]
+    length, l, r = longest_increasing_run(a)
+    print(length, l, r)