Posts

Leetcode- 144, 589, 226, offer - 32, 110, 112, 105, 222, offer - 54, offer - 26, 662, 968

1. List is a special tree.
2. The number of nodes is one more than the number of edges.
3. Nodes with degree 0 have one more node than those with degree 2.

Leetcode- 03.04, 682, 844, 946, 20, 1021, 1249, 145, 331, 227, 636, 1124

The stack can handle problems with full inclusion relation.

Leetcode- 622, 641, 1670, 933, 17.09, 859, 969, 621

• CPU Hyper-Threading Technology
• Task queues for thread pools

Leetcode- 141, 142, 202, 206, 92, 25, 61, 19, 83, 82, 86, 138

Problem solving tips

1. Determine the circle in a list: Fast & Slow pointer.

2. Head address may change: Create a virtual head node.

1. Linked list consists of two parts: Data field and Pointer field.
2. time complexity: search O(n), insert O(1), delete O(1).

First of all, a prime number has the property that it is only divisible by 1 and itself. Our goal is to filter out the prime numbers in the given range, for example, if the range is 1-10, the answer is 2, 3, 5, 7.

Two questions

1. How to find the shortest paths when we want to find the target thing, based on item correspondence？
2. Give you two glasses of water without scale, and only know the capacity, we also have infinite water to use, please give us a solution that can get our target water in the glass, for example, we hope to get 20 water after some operation, and the capacity of the two glasses of water are 90 and 40, please print the process of our operation.