The LeetCode Beginner’s Guide-Day#1

The LeetCode Beginner’s Guide Day#1

Today, I started my programming journey with LeetCode!

Its my Day#1 and I started with Beginner’s Guide.

These are the four problems I solved/looked into today.

2235. Add Two Integers

Given two integers num1 and num2, return the sum of the two integers.

class Solution(object):
    def sum(self, num1, num2):
        """
        :type num1: int
        :type num2: int
        :rtype: int
        """
        return int(num1)+ int(num2)

Accepted
Runtime: 12 ms
Case 1
Case 2
Input
num1 =
12
num2 =
5
Output
17
Expected
17

Input
num1 =
-10
num2 =
4
Output
-6
Expected
-6

2236. Root Equals Sum of Children

You are given the root of a binary tree that consists of exactly 3 nodes: the root, its left child, and its right child.

Return true if the value of the root is equal to the sum of the values of its two children, or false otherwise.

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution(object):
    def checkTree(self, root):
        """
        :type root: Optional[TreeNode]
        :rtype: bool
        """
        return root.val==root.left.val+root.right.val

Input
root =
[10,4,6]
Output
true
Expected
true

Input
root =
[5,3,1]
Output
false
Expected
false

1480. Running Sum of 1d Array

Given an array nums. We define a running sum of an array as runningSum[i] = sum(nums[0]…nums[i]).

Return the running sum of nums.

class Solution(object):
    def runningSum(self, nums):
        """
        :type nums: List[int]
        :rtype: List[int]
        """
        s=[]
        for i in range(len(nums)):
            s.append(sum(nums[:i+1]))
        return s
        

Input
nums =
[1,2,3,4]
Output
[1,3,6,10]
Expected
[1,3,6,10]

Input
nums =
[1,1,1,1,1]
Output
[1,2,3,4,5]
Expected
[1,2,3,4,5]

Input
nums =
[3,1,2,10,1]
Output
[3,4,6,16,17]
Expected
[3,4,6,16,17]

198. House Robber

You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is that adjacent houses have security systems connected and it will automatically contact the police if two adjacent houses were broken into on the same night.

Given an integer array nums representing the amount of money of each house, return the maximum amount of money you can rob tonight without alerting the police.

Input: nums = [1,2,3,1]
Output: 4
Explanation: Rob house 1 (money = 1) and then rob house 3 (money = 3).
Total amount you can rob = 1 + 3 = 4.

Input: nums = [2,7,9,3,1]
Output: 12
Explanation: Rob house 1 (money = 2), rob house 3 (money = 9) and rob house 5 (money = 1).
Total amount you can rob = 2 + 9 + 1 = 12.

 class Solution(object):
     def rob(self, nums):
         """
         :type nums: List[int]
         :rtype: int
         """
         a,b=0,0
         for i in nums:
             a,b=max(a,b), a+i
         return max(a,b)