Learning content: Weight segment tree + dp + Hash permutations
Complete number of questions: 4 title
Read the case: 6 Ye
Do questions Summary:
HUD 5249: https://www.cnblogs.com/buhuiflydepig/p/11287074.html
Cattle off more school fifth G title: https://www.cnblogs.com/buhuiflydepig/p/11289557.html
AcWing 137: https://www.cnblogs.com/buhuiflydepig/p/11291125.html
AcWing 138: https://www.cnblogs.com/buhuiflydepig/p/11291439.html
Experience:
Today learned about the permutations and combinations, discovered Pascal's Triangle and permutations and combinations are related, really everywhere in mathematics, wrote a title next tree line weight, feel and learn before the President of the trees were similar (that is, by the Chairman of the tree more stars weights segment tree formed), equivalent to brush up a bit Chairman of the tree, also learned about this amazing Hash algorithm, feeling sometimes too much data on it in the past with Hash cards, today AcWing 138 of this title, I began to write the string, but TLE, and found a substr () function is part of the string with the interception, and must be string, use: string.substr (). Is relatively simple, the back of a string Hash wrote about, after a cross out of it, Hash is easy to use, to know that this is a magical algorithm ...