Python紅/黑樹狀結構實現(帶樹的圖形化展示方法)__Python

BLACK = 0RED = 1#graphic elements of rbtree for printingVC = '│'HC = '─'SIZE = 3RIG = '┌' + HC * SIZELEF = '└' + HC * SIZESP = chr(32)IND1 = SP * (SIZE + 1)IND2 = VC + SP * SIZEclass rbnode(object):    def __init__(self, key=None, value=None, color=BLACK):        self.key = key        self.value = value        self.color = color        self.left = None        self.right = None        self.p = None    def __repr__(self):        return '%s%s%s' % (self.key,'◆' if self.color is BLACK else '◇',self.value )class rbtree(object):    def __init__(self, data=False,default_value=0):        self.nil = rbnode()        self.root = self.nil        self.default_value = default_value #for method: force_search        if hasattr(data, '__iter__'):            for key, value in data:                self.insert(rbnode(key,value))                def __repr__(self):        return '\n'.join(self.graph())    def graph(self, x=False, prefix=''):        "beautifully print rbtree, big key node first"        if x is False:            x = self.root        if x is not self.nil:            p = x.p            last_prefix = ''            if p is not self.nil:                pp = p.p                last_prefix = LEF if p.left is x else RIG                if pp is not self.nil:                    if (pp.left is p) is (p.left is x):                        prefix = prefix + IND1                    else:                        prefix = prefix + IND2            yield from self.graph(x.right, prefix)            yield '%s%s%s' % (prefix, last_prefix, x)            yield from self.graph(x.left, prefix)    def search(self, key, x=False):        "find node according to key, return self.nil if not found"        if x is False:            x = self.root        while (x is not self.nil) and (key != x.key):            if key < x.key:                x = x.left            else:                x = x.right        return x    def insert(self, z):        "insert z node with key and value"        y = self.nil        x = self.root        while x is not self.nil:            y = x            if z.key < x.key:                x = x.left            else:                x = x.right        z.p = y        if y is self.nil:            self.root = z        elif z.key < y.key:            y.left = z        else:            y.right = z        z.left = self.nil        z.right = self.nil        z.color = RED        self.insert_fixup(z)    def delete(self, z):        y = z        y_original_color = y.color        if z.left is self.nil:            x = z.right            self.transplant(z, x)        elif z.right is self.nil:            x = z.left            self.transplant(z, x)        else:            y = self.minimum(z.right)            y_original_color = y.color            x = y.right            if y.p is z:                x.p = y            else:                self.transplant(y, x)                y.right = z.right                y.right.p = y            self.transplant(z, y)            y.left = z.left            y.left.p = y            y.color = z.color        if y_original_color is BLACK:            self.delete_fixup(x)    def is_empty(self):        return self.root is self.nil    def right_walk(self, x=False):        if x is False:            x = self.root        if x is not self.nil:            yield from self.right_walk(x.right)            yield x            yield from self.right_walk(x.left)    def left_walk(self, x=False):        if x is False:            x = self.root        if x is not self.nil:            yield from self.left_walk(x.left)            yield x            yield from self.left_walk(x.right)    def force_search(self,key):        y = self.nil        x = self.root        while x is not self.nil:            if key == x.key:                return x            y = x            if key < x.key:                x = x.left            else:                x = x.right        z = rbnode()        original_z = z        z.key = key        z.value = self.default_value        z.p = y        if y is self.nil:            self.root = z        elif z.key < y.key:            y.left = z        else:            y.right = z        z.left = self.nil        z.right = self.nil        z.color = RED        self.insert_fixup(z)        return original_z            def maximum(self, x=False):        if x is False:            x = self.root        while x.right is not self.nil:            x = x.right        return x    def minimum(self, x=False):        if x is False:            x = self.root        while x.left is not self.nil:            x = x.left        return x    def successor(self, x):        "return node with smallest key greater than x.key"        if x.right is not self.nil:            return self.minimum(x.right)        y = x.p        while (y is not self.nil) and (x is y.right):            x = y            y = y.p        return y    def predecessor(self, x):        "return node with biggest key lower than x.key"        if x.left is not self.nil:            return self.maximum(x.left)        y = x.p        while (y is not self.nil) and (x is y.left):            x = y            y = y.p        return y    def left_rotate(self, x):        y = x.right        x.right = y.left        if y.left is not self.nil:            y.left.p = x        y.p = x.p        if x.p is self.nil:            self.root = y        else:            if x is x.p.left:                x.p.left = y            else:                x.p.right = y        y.left = x        x.p = y    def right_rotate(self, x):        y = x.left        x.left = y.right        if y.right is not self.nil:            y.right.p = x        y.p = x.p        if x.p is self.nil:            self.root = y        else:            if x is x.p.right:                x.p.right = y            else:                x.p.left = y        y.right = x        x.p = y    def insert_fixup(self, z):        while z.p.color is RED:            if z.p is z.p.p.left:                y = z.p.p.right                if y.color is RED:                    z.p.color = BLACK                    y.color = BLACK                    z.p.p.color = RED                    z = z.p.p                else:                    if z is z.p.right:                        z = z.p                        self.left_rotate(z)                    z.p.color = BLACK                    z.p.p.color = RED                    self.right_rotate(z.p.p)            else:                y = z.p.p.left                if y.color is RED:                    z.p.color = BLACK                    y.color = BLACK                    z.p.p.color = RED                    z = z.p.p                else:                    if z is z.p.left:                        z = z.p                        self.right_rotate(z)                    z.p.color = BLACK                    z.p.p.color = RED                    self.left_rotate(z.p.p)        self.root.color = BLACK    def delete_fixup(self, x):        while (x is not self.root) and (x.color is BLACK):            if x is x.p.left:                w = x.p.right                if w.color is RED:                    w.color = BLACK                    x.p.color = RED                    self.left_rotate(x.p)                    w = x.p.right                if (w.left.color is BLACK) and (w.right.color is BLACK):                    w.color = RED                    x = x.p                else:                    if w.right.color is BLACK:                        w.left.color = BLACK                        w.color = RED                        self.right_rotate(w)                        w = x.p.right                    w.color = x.p.color                    x.p.color = BLACK                    w.right.color = BLACK                    self.left_rotate(x.p)                    x = self.root            else:                w = x.p.left                if w.color is RED:                    w.color = BLACK                    x.p.color = RED                    self.right_rotate(x.p)                    w = x.p.left                if (w.right.color is BLACK) and (w.left.color is BLACK):                    w.color = RED                    x = x.p                else:                    if w.left.color is BLACK:                        w.right.color = BLACK                        w.color = RED                        self.left_rotate(w)                        w = x.p.left                    w.color = x.p.color                    x.p.color = BLACK                    w.left.color = BLACK                    self.right_rotate(x.p)                    x = self.root        x.color = BLACK    def transplant(self, u, v):        if u.p is self.nil:            self.root = v        elif u is u.p.left:            u.p.left = v        else:            u.p.right = v        v.p = u.pif __name__ == '__main__':    trd={'a':7,'b':1,'c':8,'d':2,'e':3}    tr=rbtree(trd.items())    print("after build from dict:")    print(tr)    for c in 'sfsdfsahfweruoiwejuckjdflsfj':        nd = tr.force_search(c)        nd.value += 1    print("\nafter insert from a string:")    print(tr)    while tr.root!=tr.nil:        tr.delete(tr.root)    print("\nafter delete all node:")    print(tr)

列印結果: