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from pyalgs.algorithms.commons.util import less, exchange, greater |
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View Code Duplication |
class MinPQ(object): |
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pq = None |
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N = 0 |
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def __init__(self, capacity=None): |
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if capacity is None: |
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capacity = 10 |
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self.pq = [0] * capacity |
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def enqueue(self, key): |
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self.N += 1 |
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if self.N == len(self.pq): |
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self.resize(len(self.pq) * 2) |
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self.pq[self.N] = key |
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self.swim(self.N) |
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def swim(self, k): |
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while k > 1: |
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parent = k // 2 |
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if less(self.pq[k], self.pq[parent]): |
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exchange(self.pq, k, parent) |
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k = parent |
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else: |
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break |
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def del_min(self): |
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if self.is_empty(): |
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return None |
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key = self.pq[1] |
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exchange(self.pq, 1, self.N) |
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self.N -= 1 |
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if self.N == len(self.pq) // 4: |
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self.resize(len(self.pq) // 2) |
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self.sink(self.pq, 1, self.N) |
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return key |
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@staticmethod |
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def sink(tmp, k, n): |
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while k * 2 <= n: |
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child = k * 2 |
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if child < n and less(tmp[child + 1], tmp[child]): |
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child = child + 1 |
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if less(tmp[child], tmp[k]): |
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exchange(tmp, child, k) |
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k = child |
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else: |
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break |
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def resize(self, new_size): |
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tmp = [0] * new_size |
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for k in range(min(new_size, len(self.pq))): |
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tmp[k] = self.pq[k] |
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self.pq = tmp |
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def is_empty(self): |
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return self.N == 0 |
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def size(self): |
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return self.N |
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def iterate(self): |
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tmp = [0] * (self.N + 1) |
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for k in range(self.N + 1): |
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tmp[k] = self.pq[k] |
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n = self.N |
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while n >= 1: |
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key = tmp[1] |
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exchange(tmp, 1, n) |
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n -= 1 |
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self.sink(tmp, 1, n) |
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yield key |
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@staticmethod |
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def create(): |
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return MinPQ() |
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View Code Duplication |
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class MaxPQ(object): |
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pq = None |
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N = 0 |
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def __init__(self, capacity=None): |
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if capacity is None: |
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capacity = 10 |
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self.pq = [0] * capacity |
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def enqueue(self, key): |
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if self.N == len(self.pq): |
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self.resize(len(self.pq) * 2) |
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self.N += 1 |
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self.pq[self.N] = key |
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self.swim(self.N) |
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def swim(self, k): |
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while k > 1: |
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parent = k // 2 |
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if greater(self.pq[k], self.pq[parent]): |
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exchange(self.pq, k, parent) |
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k = parent |
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else: |
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break |
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def del_max(self): |
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if self.is_empty(): |
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return None |
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key = self.pq[1] |
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exchange(self.pq, 1, self.N) |
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self.N -= 1 |
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if self.N == len(self.pq) // 4: |
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self.resize(len(self.pq) // 2) |
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self.sink(self.pq, 1, self.N) |
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return key |
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@staticmethod |
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def sink(tmp, k, n): |
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while k * 2 <= n: |
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child = k * 2 |
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if child < n and greater(tmp[child + 1], tmp[child]): |
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child = child + 1 |
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if greater(tmp[child], tmp[k]): |
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exchange(tmp, child, k) |
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k = child |
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else: |
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break |
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def resize(self, new_size): |
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tmp = [0] * new_size |
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for k in range(min(new_size, len(self.pq))): |
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tmp[k] = self.pq[k] |
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self.pq = tmp |
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def is_empty(self): |
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return self.N == 0 |
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def size(self): |
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return self.N |
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def iterate(self): |
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tmp = [0] * (self.N + 1) |
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for k in range(self.N + 1): |
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tmp[k] = self.pq[k] |
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n = self.N |
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while n >= 1: |
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key = tmp[1] |
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exchange(tmp, 1, n) |
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n -= 1 |
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self.sink(tmp, 1, n) |
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yield key |
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@staticmethod |
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def create(): |
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return MaxPQ() |
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class IndexMinPQ(object): |
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keys = None |
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pq = None |
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qp = None |
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N = 0 |
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def __init__(self, size): |
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self.keys = [None] * (size+1) |
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self.pq = [0] * (size+1) |
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self.qp = [0] * (size+1) |
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def insert(self, index, key): |
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self.keys[index] = key |
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self.N += 1 |
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self.pq[self.N] = index |
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self.qp[index] = self.N |
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self.swim(self.N) |
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def decrease_key(self, index, key): |
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self.keys[index] = key |
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k = self.qp[index] |
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self.swim(k) |
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def contains_index(self, index): |
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return self.keys[index] is not None |
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def swim(self, k): |
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while k > 1: |
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parent = k / 2 |
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View Code Duplication |
if less(self.keys[self.pq[k]], self.keys[self.pq[parent]]): |
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exchange(self.pq, k, parent) |
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self.qp[self.pq[k]] = k |
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self.qp[self.pq[parent]] = parent |
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k = parent |
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else: |
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break |
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def get(self, index): |
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return self.keys[index] |
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def min_key(self): |
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return self.keys[self.pq[1]] |
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def del_min(self): |
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index = self.pq[1] |
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exchange(self.pq, 1, self.N) |
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self.qp[self.pq[1]] = 1 |
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self.qp[self.pq[self.N]] = self.N |
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self.N -= 1 |
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self.sink(1) |
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return index |
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def sink(self, k): |
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while 2 * k <= self.N: |
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child = 2 * k |
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if child < self.N and less(self.keys[self.pq[child]], self.keys[self.pq[child+1]]): |
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child = child+1 |
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View Code Duplication |
if less(self.keys[self.pq[child]], self.keys[self.pq[k]]): |
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exchange(self.pq, k, child) |
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self.qp[self.pq[k]] = k |
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self.qp[self.pq[child]] = child |
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k = child |
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else: |
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break |
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def is_empty(self): |
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return self.N == 0 |
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def size(self): |
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return self.N |
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