629. K 个逆序对数组 - 对于一个整数数组 nums,逆序对是一对满足 0 <= i < j < nums.length 且 nums[i] > nums[j]的整数对 [i, j] 。 给你两个整数 n 和 k,找出所有包含从 1 到 n 的数字,且恰好拥有 k 个 逆序对 的不同的数组的个数。由于答案可能很大,只需要返回对 10
所以,为了提高大家的算法能力,这个公众号后续每天带大家做一道算法题,题目就从LeetCode上面选 ! 今天和大家聊的问题叫做K个逆序对数组,我们先来看题面: leetcode.cn/problems/k- For an integer array nums, an inverse pair is a pair of integers [i, j] where 0 <= i < j < nums.length and nums...
Given two integers n and k, find how many different arrays consist of numbers from 1 to n such that there are exactly k inverse pairs. We define an inverse pair as following: For ith and jth element in the array, if i < j and a[i] > a[j] then it’s an inverse pair; Otherwis...
https://leetcode.com/problems/k-inverse-pairs-array/description/ 【题意】 给定n和k,求正好有k个逆序对的长度为n的序列有多少个,0<=k<=1000, 1<=n<=1000,答案模1e9+7 【思路】 dp[i][j]表示正好有j个逆序对的长度为i的序列的方案数,最终我们要求的就是dp[n][k] 考虑dp[i+1][j]和dp[i...
The array [1,3,2] and [2,1,3] have exactly 1 inverse pair. Note: The integernis in the range [1, 1000] andkis in the range [0, 1000]. 这道题给了我们1到n总共n个数字,让我们任意排列数组的顺序,使其刚好存在k个翻转对,所谓的翻转对,就是位置在前面的数字值大,而且题目中表明了结果会...
来源:力扣(LeetCode) 链接:https://leetcode-cn.com/problems/k-inverse-pairs-array 著作权归领扣网络所有。商业转载请联系官方授权,非商业转载请注明出处。 2. 动态规划 f(i,j) 表示i个数,j个逆序对的组合方式种类 i个数的j个逆序对的组合,可以在i-1个数的基础上得到 把第i个数插入到前面i-1的i个...
https://leetcode.com/problems/k-inverse-pairs-array/description/ Given two integers n and k, find how many different arrays consist of numbers from 1 to n such that there are exactly k inverse pairs. We define an inverse pair as following: For ith and jth element in the array, if i ...
629 K Inverse Pairs Array K个逆序对数组 Description: For an integer array nums, an inverse pair is a pair of integers [i, j] where 0 <= i < j < nums.length and nums[i] > nums[j]. Given two integers n and k, return the number of different arrays consist of numbers from 1 to...
The array [1,3,2] and [2,1,3] have exactly 1 1. 2. 3. 4. Note: The integer n is in the range [1, 1000] and k is in the range [0, 1000]. class Solution { public int kInversePairs(int n, int k) { long[][] dp = new long[n+1][k+1]; ...
The array [1,3,2] and [2,1,3] have exactly 1 inverse pair. Solution: This problem's dp solution is challenging to construct 1. reference the tutorial of the solution;https://leetcode.com/articles/k-inverse-pairs-array/ very great explanation for 8 approaches, I only came up with the...