[CF908G]New Year and Original Order(动态规划) 题面 洛谷 CF 题解 设\(f[i][j][k][0/1]\)表示当前填到了第\(i\)位,有\(j\)个大于等于\(k\)的数,是否卡到上界的方案数. 这个东西算完之后,等价于默认排好序了. 看起来可以枚举每个数字出现在第几位了. 然而实际上不知道这个数字的出现次数,所以不能按照\(10^j*k\)这样子计算贡献. 怎么办呢,假设前面有\(j\)个数大于\(k\)的数,那么就产生\(\sum_{i=0}^{j…

[CF908G]New Year and Original Order 题意:令S(i)表示将i中所有数位上的数拿出来,从小到大排序后组成一个新的数的值.如S(50394)=3459.求$\sum\limits_{i=1}^nS(i)$. $n\le 10^{700}$. 题解:比较难的数位DP.我们考虑分别计算每个数字的贡献.令f0[i][a][b]表示考虑到第i位数,其中数字a的最高为是b的数的数量,再令f1[i][a][b]表示a这个数的贡献.再设g0,g1表示小于等于n的所有数的DP值.…

[CF908G]New Year and Original Order 题面 洛谷 题解 设\(f[i][j][k][l]\)表示当前在第\(i\)位有\(j\)位大于等于\(k\),当前有没有卡上界的方案数 则枚举新加的数\(p\),有 \[ f[i+1][j+(p\geq k)][k][l|(p<a_i)]=\sum f[i][j][k][l] \] 我们最后统计答案的时候枚举\(k\) 有 \[ ans=\underbrace{111...11}_{j个1}*(f[i][j][k][0]+…

Binary Tree Zigzag Level Order Traversal Given a binary tree, return the zigzag level order traversal of its nodes' values. (ie, from left to right, then right to left for the next level and alternate between). For example:Given binary tree {3,9,20,#…

Given a binary tree, return the zigzag level order traversal of its nodes' values. (ie, from left to right, then right to left for the next level and alternate between). For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return its…

Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root). For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return its bottom-up level order tr…

Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return its level order traversal as: [ [3], [9,20], [15,7] ] So…

problem 429. N-ary Tree Level Order Traversal solution1:Iteration /* // Definition for a Node. class Node { public: int val; vector<Node*> children; Node() {} Node(int _val, vector<Node*> _children) { val = _val; children = _children; } }; */…

题目: Given a binary tree, return the zigzag level order traversal of its nodes' values. (ie, from left to right, then right to left for the next level and alternate between). For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return…

Suppose that a website contains two tables, the Customers table and the Orders table. Write a SQL query to find all customers who never order anything. Table: Customers. +----+-------+ | Id | Name | +----+-------+ | 1 | Joe | | 2 | Henry | | 3 | Sam…