Dsa

a linked list If we use two pointers slow and fast, the first one moves forward one step at a time, and the second one moves forward two steps at a time. Eventually, the two pointers will meet somewhere. In the above example, they meet at number 9 (or G). G is where two-pointers fast and slow meet. E is the entrance of the loop. S is the first node of the linked list. F is the distance from the chain’s beginning to the loop’s entrance (from S to E). (eg: 1 – 3 – 5) a is the distance from the loop’s entrance to the point where two pointers meet (from E to G). (eg: 5 – 6 – 7 – 8 – 9) C is the length of the loop. (eg: the loop is 5 – 6 – 7 – 8 – 9 – 10, the length is 6 ) The total distance that the slow pointer has moved is $F + a + xC$. $x$ is the number of times the slow pointer completes the loop. The total distance that the fast pointer has moved is $F + a + yC$. Likewise, $y$ is the number of times the fast pointer completes the loop. ...

1. Definition set is a collection of unique elements. the word disjoin means non-overlapping – two sets are considered as disjoining if they have no element in common disjoin-set contains a collection of non-overlapping sets it has two method find(x): return the representative element of the set that contains of x if u and v are in the same set, find(u) = find(v) union(u, v): merge two sets that contain u and v after merging, find(v) = find(u) 2. Implementations View the visualization of the data structure here. ...

To demonstrate what is the difference between object hash code and object equal, I would like to start with a simple example in Python. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 class Person: def __init__(self, name: str, age: int) -> None: self.name = name self.age = age def __repr__(self) -> str: return f'{self.name} {self.age}' john = Person('John', 18) eventRegister = {} # John want to join the event eventRegister[john] = True # In the next day, # he changes his mind john = Person('John', 18) eventRegister[john] = False print(f'registers: {eventRegister}') # Check john = Person('John', 18) print(f'Will John join the event? {eventRegister[john]}') It’s quite simple, right? I define a new Person class that has two properties age and name. And then I defined a map, to check if a person join the event or not. ...