堆排序做的,没有全部排序,找到第k个就结束 public int findKthLargest(int[] nums, int k) { int num = 0; if (nums.length <= 1) return nums[0]; int heapSize = nums.length; //1.构建最大堆 int half = (heapSize-2)/2; for (int i = half;i >= 0;i--) { adjust(nums,heapSize,i); } while…
题目:给定一个一维数组,如[1,2,4,4,3,5],找出数组中第k大的数字出现多少次. 例如:第2大的数是4,出现2次,最后输出 4,2 function getNum(arr, k){ // 数组排序->从大到小 arr.sort((a, b)=>{ return b-a; }); let uniqarr = Array.from(new Set(arr)); // 数组去重 let tar = uniqarr[k-1]; // 找到目标元素 let index = arr.indexOf…
作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 方法一:移除最大值 方法二:排序 方法三:大顶堆 方法四:partition 日期 题目地址:https://leetcode.com/problems/kth-largest-element-in-an-array/description/ 题目描述 Find the kth largest element in an unsorted array…
传送门 有一个整数数组,请你根据快速排序的思路,找出数组中第K大的数. 给定一个整数数组a,同时给定它的大小n和要找的K(K在1到n之间),请返回第K大的数,保证答案存在. 测试样例: [1,3,5,2,2],5,3 返回:2 note: 注意手写快排的时候: while(i < j) { while(j > i && a[j] > a[left]) j--; while(i < j && a[i] <= a[left]) i++; if(i…
Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. For example,Given [3,2,1,5,6,4] and k = 2, return 5. Note: You may assume k is always valid, 1 ≤ k ≤ array's…
注意multiset的一个bug: multiset带一个参数的erase函数原型有两种.一是传递一个元素值,如上面例子代码中,这时候删除的是集合中所有值等于输入值的元素,并且返回删除的元素个数:另外一种是传递一个指向某个元素的iterator,这时候删除的就是这个对应的元素,无返回值. https://www.cnblogs.com/lakeone/p/5600494.html 删除的时候一定不能删除指针,只能删除迭代器 leetcode那个题就是在这个地方出错的: Input: [3,2,3…
lc 215 Kth Largest Element in an Array 215 Kth Largest Element in an Array Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. For example, Given [3,2,1,5,6,4]…
题目链接:https://leetcode.com/problems/kth-largest-element-in-an-array/ 215. Kth Largest Element in an Array My Submissions Question Total Accepted: 43442 Total Submissions: 136063 Difficulty: Medium Find the kth largest element in an unsorted array. Not…
Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. Example 1: Input: [3,2,1,5,6,4] and k = 2 Output: 5 Example 2: Input: [3,2,3,1,2,4,5,5,6] and k = 4 Output:…
Kth Largest Element in an Array Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. For example,Given [3,2,1,5,6,4] and k = 2, return 5. Note: You may assume k…
Kth Largest Element in an Array Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. Example 1: Input: [3,2,1,5,6,4] and k = 2 Output: 5 Example 2: Input: [3,2,3…
Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once. Find all the elements of [1, n] inclusive that do not appear in this array. Could you do it without extra space and in O(n) runtime?…
Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. For example,Given [3,2,1,5,6,4] and k = 2, return 5. [一句话思路]:快速选择:先利用pivot进行两侧的排序,再选一侧递归查找. [一刷]: Kth函数中要调用一…
Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. Example 1: Input: [3,2,1,5,6,4] and k = 2 Output: 5 Example 2: Input: [3,2,3,1,2,4,5,5,6] and k = 4 Output:…
Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. For example, Given [3,2,1,5,6,4] and k = 2, return 5. 解题思路: 本题是<算法导论>原题,9.2节用归并的思路给出了时间复杂度为O(n)的算法,9.3节给出了最…
Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. For example,Given [3,2,1,5,6,4] and k = 2, return 5. Note: You may assume k is always valid, 1 ≤ k ≤ array's…
Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. For example,Given [3,2,1,5,6,4] and k = 2, return 5. Note: You may assume k is always valid, 1 ≤ k ≤ array's…
Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. For example, Given [3,2,1,5,6,4] and k = 2, return 5. 题解1:玩赖的写法,直接调用java中的sort函数,之后选取倒数第k个元素,即为所有. public in…
Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. Example 1: Input: [3,2,1,5,6,4] and k = 2 Output: 5 Example 2: Input: [3,2,3,1,2,4,5,5,6] and k = 4 Output:…
Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. Example 1: Input: [3,2,1,5,6,4] and k = 2 Output: 5 Example 2: Input: [3,2,3,1,2,4,5,5,6] and k = 4 Output:…
Given an array of integers, 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once. Find all the elements that appear twice in this array. Could you do it without extra space and in O(n) runtime? Example: Input: [4,3,2,7,…
一  问题描述: 找出 m 个整数中第 k(0<k<m+1)大的整数. 二  举例: 假设有 12 个整数:data[1, 4, -1, -4, 9, 8, 0, 3, -8, 11, 2, -9],请找出第 5 大的数(容易知道是0). 三   算法思路:        一种基于快排思想的算法可以在 O(n) 复杂度内找到第k大的数,首先要知道 partition 这个函数,它可以调整一个序列 使小于 key 的元素都排在 key 左边,大于 key 的元素都排在 key 右边,key 可以…
问题:找出一个数组里面前K个最大数. 解法一(直接解法): 对数组用快速排序,然后直接挑出第k大的数.这种方法的时间复杂度是O(Nlog(N)).N为原数组长度. 这个解法含有很多冗余,因为把整个数组都排序了,而实际上我们不需要这样做. 解法二(K数组排序): 首先,创建一个长度为K的空数组.从原数组中先挑出K个数进行排序并放到这个空数组中.这一步的时间复杂度是O(Klog(K)). 接着,从剩下的N-K个值中,依次遍历并与上面数组的末尾的数(即里面的最大数)相比较,并插入到合适位置,需要执行(…
class Solution { public: int quicksort(vector<int>& nums, int start, int end, int k){ int i = start; int j = end; int x = nums[i]; while (i<j){ //快排核心… while (nums[j]<x && i<j) j--; if (i<j) nums[i++] = nums[j]; while (nums[i…
题目:在无序的数组中找到第k大的元素,也就是若长度为n的数组从小到大排列时,下标为n-k的元素. 注意Example2:第4大的元素是4,也就是数组中出现的两个5分别是第2大和第3大的数字. 解法一:直接利用sort函数排序后,取第k大的元素. class Solution { public: int findKthLargest(vector<int>& nums, int k) { sort(nums.begin(), nums.end()); return nums[nums.s…
在未排序的数组中找到第 k 个最大的元素.请注意,它是数组有序排列后的第 k 个最大元素,而不是第 k 个不同元素.例如,给出 [3,2,1,5,6,4] 和 k = 2,返回 5.注意事项:你可以假设 k 总是有效的,1 ≤ k ≤ 数组的长度. 详见:https://leetcode.com/problems/kth-largest-element-in-an-array/description/ Java实现: 方法一: class Solution { public int findKt…
mycode  77.39% class Solution(object): def findKthLargest(self, nums, k): """ :type nums: List[int] :type k: int :rtype: int """ nums.sort() return nums[-k] 参考 class Solution(object): def findKthLargest(self, nums, k): nums.s…
[抄题]: Given an array of integers, 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once. Find all the elements that appear twice in this array. Could you do it without extra space and in O(n) runtime? Example: Input: [4,…
「HW面试题」 [题目] 给定一个整数数组,如何快速地求出该数组中第k小的数.假如数组为[4,0,1,0,2,3],那么第三小的元素是1 [题目分析] 这道题涉及整数列表排序问题,直接使用sort方法按照ASCII码排序即可 [解答] #!/Users/minutesheep/.pyenv/shims/python # -*- coding: utf-8 -*- num = [4, 0, 1, 0, 2, 3] num.sort() # 按照ASCII码排序 print(num[(3-1)])…
leetcode面试准备:Kth Largest Element in an Array 1 题目 Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. For example, Given [3,2,1,5,6,4] and k = 2, return 5. Note…