Python please help

[jane_0001]

1. Binary Search Tree
There is a binary search tree and a number N. The task is to find the greatest number in the binary search tree that is less than or equal to N. Print the value of the element if it exists otherwise print -1. You can modify the following code. (3 points)

# A utility class that represents an individual node in a BST
class Node:
    def __init__(self,key):
        self.left = None
        self.right = None
        self.val = key
# A utility function to insert a new node with the given key
def insert(root,node):
    if root is None:
        root = node
    else:
        if root.val < node.val:
            if root.right is None:
                root.right = node
else:
                insert(root.right, node)
        else:
            if root.left is None:
                root.left = node
            else:
                insert(root.left, node)
# A utility function to do in-order tree traversal
def inorder(root):
    if root:
        inorder(root.left)
        print(root.val)
        inorder(root.right)
 # Driver program to test the above functions # Let us create the following BST
# 50
#/\
# 30 70 #/\/\
# 2040 6080
r = Node(50) insert(r,Node(30)) insert(r,Node(20)) insert(r,Node(40)) insert(r,Node(70)) insert(r,Node(60)) insert(r,Node(80))
# Print in-order traversal of the BST
inorder(r)

2. Coloring Problem
Please modify the following backtracking code and increase efficiency of the problem through “Least Constraint Value” approach.

class Graph():
    def __init__(self, vertices):
        self.V = vertices
self.graph = [[0 for column in range(vertices)] for row in range(vertices)]
    # A utility function to check if the current color assignment
    # is safe for vertex v
    def isSafe(self, v, colour, c):
        for i in range(self.V):
            if self.graph[v][i] == 1 and colour[i] == c:
                return False
        return True
    # A recursive utility function to solve m
    # coloring  problem
    def graphColourUtil(self, m, colour, v):
        if v == self.V:
            return True
        for c in range(1, m+1):
            if self.isSafe(v, colour, c) == True:
                colour[v] = c
                if self.graphColourUtil(m, colour, v+1) == True:
                    return True
                colour[v] = 0

def graphColouring(self, m):
    colour = [0] * self.V
    if self.graphColourUtil(m, colour, 0) == False:
return False
    for c in colour:
        if c == 0:
            print (c),
            print ("Solution does not exist")
            return False
print (c),
    # Print the solution
    print ("Solution exist and Above are the assigned colours:")
return True

---

thank you so much :)

[ichabod801]

What have you tried?