add MaxPQ MinPQ

algs4/max_pq.py

@@ -0,0 +1,43 @@
+class MaxPQ:
+
+    def __init__(self):
+        self.pq = []
+
+    def insert(self, v):
+        self.pq.append(v)
+        self.swim(len(self.pq) - 1)
+
+    def max():
+        return self.pq[1]
+
+    def del_max(self, ):
+        m = self.pq[0]
+        self.pq[0], self.pq[-1] = self.pq[-1], self.pq[0]
+        self.pq = self.pq[:-1]
+        self.sink(0)
+        return m
+
+    def is_empty(self, ):
+        return not self.pq
+
+    def size(self, ):
+        return len(self.pq)
+
+    def swim(self, k):
+        while k > 0 and self.pq[(k - 1) // 2] < self.pq[k]:
+            self.pq[k], self.pq[
+                (k - 1) // 2] = self.pq[(k - 1) // 2], self.pq[k]
+            k = k // 2
+
+    def sink(self, k):
+        N = len(self.pq)
+
+        while 2 * k + 1 <= N - 1:
+            j = 2 * k + 1
+            if j < N - 1 and self.pq[j] < self.pq[j + 1]:
+                j += 1
+
+            if self.pq[k] > self.pq[j]:
+                break
+            self.pq[k], self.pq[j] = self.pq[j], self.pq[k]
+            k = j

algs4/min_pq.py

@@ -0,0 +1,44 @@
+class MinPQ:
+
+    def __init__(self):
+        self.pq = []
+
+    def insert(self, v):
+        self.pq.append(v)
+        self.swim(len(self.pq) - 1)
+
+    def min(self):
+        return self.pq[1]
+
+    def del_min(self, ):
+        m = self.pq[0]
+        self.pq[0], self.pq[-1] = self.pq[-1], self.pq[0]
+        self.pq = self.pq[:-1]
+        self.sink(0)
+        return m
+
+    def is_empty(self, ):
+        return not self.pq
+
+    def size(self, ):
+        return len(self.pq)
+
+    def swim(self, k):
+        while k > 0 and self.pq[(k - 1) // 2] > self.pq[k]:
+            self.pq[k], self.pq[
+                (k - 1) // 2] = self.pq[(k - 1) // 2], self.pq[k]
+            k = (k - 1) // 2
+
+    def sink(self, k):
+        N = len(self.pq)
+
+        while 2 * k + 1 <= N - 1:
+            j = 2 * k + 1
+            if j < N - 1 and self.pq[j] > self.pq[j + 1]:
+                j += 1
+
+            if self.pq[k] < self.pq[j]:
+                break
+
+            self.pq[k], self.pq[j] = self.pq[j], self.pq[k]
+            k = j

algs4/top_m.py

@@ -0,0 +1,19 @@
+import sys
+
+from algs4.min_pq import MinPQ
+from algs4.stack import Stack
+from algs4.transaction import Transaction
+
+M = int(sys.argv[1])
+pq = MinPQ()
+for line in sys.stdin:
+    Transaction(line)
+    pq.insert(Transaction(line))
+    if pq.size() > M:
+        pq.del_min()
+
+stack = Stack()
+while not pq.is_empty():
+    stack.push(pq.del_min())
+for t in stack:
+    print(t)

algs4/transaction.py

@@ -0,0 +1,26 @@
+class Transaction:
+
+    def __init__(self, l):
+        who, when, amount = l.split()
+        self.who = who
+        self.when = when
+        self.amount = float(amount)
+
+    def __str__(self):
+        return "%-10s %10s %8.2f" % (self.who, self.when, float(self.amount))
+
+    def __lt__(self, other):
+        return self.amount < other.amount
+
+    def __gt__(self, other):
+        return self.amount > other.amount
+
+    def __eq__(self, other):
+        return self.amount == other.amount
+
+    def hashcode(self):
+        hashcode = 1
+        hashcode = 31 * hashcode + hash(self.who)
+        hashcode = 31 * hashcode + hash(self.when)
+        hashcode = 31 * hashcode + hash(self.amount)
+        return hashcode