Created
December 10, 2011 22:48
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Implementation of intervaltree
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| class Node: | |
| def __init__(self,value): | |
| self.left = Leaf() | |
| self.right = Leaf() | |
| self.value = value | |
| self.maxima = value.high | |
| def search(tree,interval): | |
| if interval.low > tree.maxima: | |
| return [] | |
| elif interval.high < tree.value.low: | |
| return tree.left.search(interval) | |
| else: | |
| intersects = [] | |
| if interval.intersects(tree.value): | |
| intersects.append(tree.value) | |
| intersects.extend(tree.left.search(interval)) | |
| intersects.extend(tree.right.search(interval)) | |
| return intersects | |
| def insert(tree,interval): | |
| if interval.high > tree.maxima: | |
| tree.maxima = interval.high | |
| if tree.value.low >= interval.low: | |
| tree.left = tree.left.insert(interval) | |
| else: | |
| tree.right = tree.right.insert(interval) | |
| return tree | |
| def remove(tree,interval): | |
| if interval == tree.value: | |
| if isinstance(tree.left,Leaf): | |
| return tree.right | |
| elif isinstance(tree.right,Leaf): | |
| return tree.left | |
| else: | |
| # find in order predecessor | |
| pre, newLeftTree = tree._returnAndRemoveMax(tree.left) | |
| tree.left = newLeftTree | |
| tree.value = pre | |
| tree.maxima = max(tree.right.maxima,tree.value.high,tree.left.maxima) | |
| return tree | |
| elif interval.low < tree.value.low: | |
| tree.left = tree.left.remove(interval) | |
| tree.maxima = computeMaxima(tree) | |
| return tree | |
| else: | |
| tree.right = tree.right.remove(interval) | |
| tree.maxima = max(tree.right,tree.left,tree.value.high) | |
| return tree | |
| def _returnAndRemoveMax(tree): | |
| if not isinstance(tree.right,Leaf): | |
| rightValue,RemTree = tree.right._returnAndRemoveMax() | |
| tree.right = RemTree | |
| tree.maxima = max(tree.right.maxima,max(tree.value.high,tree.left.maxima)) | |
| return(rightValue,tree) | |
| else: | |
| return(tree.value,tree.left) | |
| def __str__(self): | |
| return ("(" + str(self.left) + " " + str(self.value) + "|" + | |
| str(self.maxima) + " " + str(self.right) + ")") | |
| class Interval: | |
| def __init__(self,left,right): | |
| self.low = left | |
| self.high = right | |
| def intersects(self,other): | |
| if(self.high < other.low): | |
| return False | |
| elif(other.high < self.low): | |
| return False | |
| else: | |
| return True | |
| def __str__(self): | |
| return str((self.low,self.high)) | |
| def __repr__(self): | |
| return self.__str__() | |
| class Leaf(Node): | |
| def __init__(self): | |
| self.maxima = 0 | |
| def __str__(self): | |
| return("nil") | |
| def search(self,_interval): | |
| return [] | |
| def insert(self,interval): | |
| return Node(interval) | |
| def remove(self): | |
| return self | |
| i1 = Interval(1,5) | |
| i2 = Interval(2,7) | |
| i3 = Interval(0,4) | |
| i4 = Interval(3,40) | |
| tree = Leaf() | |
| for interval in [i1,i2,i3,i4]: | |
| tree = tree.insert(interval) | |
| print(tree) | |
| print tree.search(Interval(6,8)) | |
| tree = tree.remove(i4) | |
| print(tree) |
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