A sequence of numbers is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the same. For example, these are arithmetic sequences: 1, 3, 5, 7, 9 7, 7, 7, 7 3, -1, -5, -9 The follo…

A sequence of numbers is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the same. For example, these are arithmetic sequences: 1, 3, 5, 7, 9 7, 7, 7, 7 3, -1, -5, -9 The follo…

446. Arithmetic Slices II - Subsequence Hard A sequence of numbers is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the same. For example, these are arithmetic sequences: 1,…

原题链接在这里:https://leetcode.com/problems/arithmetic-slices-ii-subsequence/ 题目: A sequence of numbers is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the same. For example, thes…

Leetcode443 题意:给一个长度1000内的整数数列,求有多少个等差的子数列. 如 [2,4,6,8,10]有7个等差子数列. 想了一个O(n^2logn)的DP算法 DP[i][j]为 对于原数列中的Ai到Ai为止 公差为j的数列的个数, 显然公差范围很大需要用到map(所以有了Logn)然而这道题用BST的map是要TLE或者MLE的 而HASH_MAP又无法使用,所以只好自己写一个hash了. 看了网上的一些解答 都是用的python 这道题用cpp还是有点麻烦. 关于动规方程 就…

A sequence of numbers is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the same. For example, these are arithmetic sequences: 1, 3, 5, 7, 9 7, 7, 7, 7 3, -1, -5, -9 The follo…

A sequence of numbers is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the same. For example, these are arithmetic sequences: 1, 3, 5, 7, 9 7, 7, 7, 7 3, -1, -5, -9 The follo…

A sequence of numbers is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the same. For example, these are arithmetic sequences: 1, 3, 5, 7, 9 7, 7, 7, 7 3, -1, -5, -9 The follo…

详见:https://leetcode.com/problems/arithmetic-slices-ii-subsequence/description/ C++: class Solution { public: int numberOfArithmeticSlices(vector<int>& A) { int res = 0, n = A.size(); vector<unordered_map<int, int>> dp(n); for (int i…

A sequence of number is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the same. For example, these are arithmetic sequence: 1, 3, 5, 7, 9 7, 7, 7, 7 3, -1, -5, -9 The followi…