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...
[Leetcode] DP--629. K Inverse Pairs Array Given two integersnandk, find how many different arrays consist of numbers from1tonsuch that there are exactlykinverse pairs. We define an inverse pair as following: Forithandjthelement in the array, ifi<janda[i]>a[j]then it's an inverse pair...
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...
629. K Inverse Pairs Array 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...
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...
lc 629. K Inverse Pairs Array https://leetcode.com/problems/k-inverse-pairs-array/ 更新:这个问题怎么都感觉有O(1)解法,解析解,真的规律太明显,Fibonacci sequence都有通项公式呢。 给一个set(1,2,3,4,5,6...n),输出有多少种排列使之有k个逆序对。 观察...
https://leetcode.com/problems/k-inverse-pairs-array/discuss/104825/Shared-my-C%2B%2B-O(n-*-k)-solution-with-explanation__EOF__ 本文作者:Veritas des Liberty 本文链接:https://www.cnblogs.com/h-hkai/p/10506927.html关于博主:评论和私信会在第一时间回复。或者直接私信我。版权声明:本博客所有...
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]. 给出两个整数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。