作者:jostree  转载请注明出处 http://www.cnblogs.com/jostree/p/4051169.html 题目链接:leetcode Permutations II 无重全排列 题目要求对有重复的数组进行无重全排列.为了保证不重复,类似于全排列算法使用dfs,将第一个数字与后面第一次出现的数字交换即可.例如对于序列1,1,2,2 有如下过程: ,1,2,2 -> 1,,2,2 -> 1,1,,2 -> 1,1,2,  -> 1,2,,2 -> 1,2…

Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1]. 这道题是之前那道Permutations 全排列的延伸,由于输入数组有可能出现重复数字,如果按照之前的算法运算,会有…

Given a collection of numbers, return all possible permutations. For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1]. 这道题是求全排列问题,给的输入数组没有重复项,这跟之前的那道Combinations 组合项 和类似,解法基本相同,但是不同点在于那道不同的数字顺序只…

原题地址:https://oj.leetcode.com/problems/permutations-ii/ 题意: Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1].…

原题地址:https://oj.leetcode.com/problems/permutations/ 题意: Given a collection of numbers, return all possible permutations. For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1]. 解题思路:穷举一个集合的全排列.这个就…

Permutations Given a collection of numbers, return all possible permutations. For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1]. SOLUTION 1: 经典的递归回溯题目,一次ACCEPT. 请也参考上一个题目LeetCode: Combination…

Given a collection of numbers, return all possible permutations. For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1]. 使用递归解决 class Solution { public: vector<bool> visit; vector<int> num;…

Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1]. Solution: public class Solution { public List<List<Intege…

Permutations Given a collection of numbers, return all possible permutations. For example, [1,2,3] have the following permutations: [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1]. 求数组元素的全排列,数组不含重复元素 算法1:递归 类似于DFS的递归. 对于包含n个元素的数组,先确定第一位置的元素,…

Given a collection of numbers, return all possible permutations. For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1]. 思路:将元素一个一个的插入,首先只有一个元素{1},此时,插入之后会的到两个vector<int>,{1,2},{2,1},然后继续插入第三个元素3…

Permutations Given a collection of numbers, return all possible permutations. For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1]. 用Python递归求全排列,回顾回顾 class Permutations: def perm(self, num, li,…

题目一 permutations 题目描述 Given a collection of numbers, return all possible permutations. For example,[1,2,3]have the following permutations:[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2], and[3,2,1]. 题二解析:   这是很经典的全排列问题,本题的解法很多.因为这里的所有数都是相异的,故笔者采用了交换元素+DFS的方法…

Permutations II Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1]. SOLUTION 1: 还是经典的递归模板.需要处理的情况是:我们先把Num排序,然…

Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1]. 解题思路: Permutations 那题输入是不包含重复元素的,故生成的排列都是不同的,II中输入元素可能相同 因…

Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2]have the following unique permutations:[1,1,2],[1,2,1], and[2,1,1]. 题意:当数列中有重复数字时,求其全排列. 思路:和permutation一样.以[1,1,2]为例,以第一个1为开始,得到…

Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1]. Show Tags Backtracking       这个就是输入一个数组,可能有重复,输出全部的排列.    …

原题是找到一组数的全排列 Given a collection of numbers, return all possible permutations. For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1]. 函数原型: vector<vector<int> > permute(vector<int> &a…

题意: 给出n个元素(可能有重复的),请产生出所有的全排列. 思路: 同版本1的有点不同,这次有可能含有重复的元素,很容易就TLE,节省时间才是关键点. 如果将一个序列中两个相同的元素交换,这个序列是仍然没有发生改变的,这也是省时间的关键点.考虑第i个位置可取的元素是nums[i-1,nums.size()-1],那么交换的时候不必要将与num[i-1]相同的元素交换到第i位了.这可以预先通过排一次序解决.排序后变成多段相同的元素接在一起,而通常只会将每段的第一个元素被换到第i个位置,考虑每段的…

题意: 给出n个元素,请产生出所有的全排列. 思路: 注意到可能会有相同的排列出现,比如 {2,2}.还有可能是乱序列(大部分情况下都是无所谓的). 递归(1):产生的过多的多余vector. class Solution { public: void recursion(vector<int> num, int i, vector<vector<int> > &res) { ==num.size()) res.push_back(num); else { fo…

写了两个,一个是直接的递归实现: class Solution { public: void swap(vector<int> &num,int left,int right) { num[left] = num[left]^num[right]; num[right] = num[left]^num[right]; num[left] = num[left]^num[right]; } void permuteHelp(vector<int> &num,int f…

最近在准备找工作的算法题,刷刷LeetCode,以下是我的解题报告索引,每一题几乎都有详细的说明,供各位码农参考.根据我自己做的进度持续更新中......                              本文地址 LeetCode:Reverse Words in a String LeetCode:Evaluate Reverse Polish Notation LeetCode:Max Points on a Line LeetCode:Sort List LeetCode:Ins…

Combination Sum Combination Sum Total Accepted: 25850 Total Submissions: 96391 My Submissions Question Solution Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. The…

Here is my collection of solutions to leetcode problems. Related code can be found in this repo: https://github.com/zhuli19901106/leetcode LeetCode - Course Schedule LeetCode - Reverse Linked List LeetCode - Isomorphic Strings LeetCode - Count Primes…

You may know that an unbounded wildcard Set<?> can hold elements of any type, and a raw type Set can also hold elements of any type. What is the difference between them? Two facts about Set<?> There are two facts about Set<?>:Item 1: Sin…

Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example, [1,1,2] have the following unique permutations: [1,1,2], [1,2,1], and [2,1,1]. 解题思路一: 发现Java for LeetCode 046 Permutations自己想多了,代码直接拿来用…

# -*- coding: utf8 -*-'''__author__ = 'dabay.wang@gmail.com' 47: Permutations IIhttps://oj.leetcode.com/problems/permutations-ii/ Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2…

# -*- coding: utf8 -*-'''__author__ = 'dabay.wang@gmail.com' 46: Permutationshttps://leetcode.com/problems/permutations/ Given a collection of numbers, return all possible permutations.For example,[1,2,3] have the following permutations:[1,2,3], [1,3…

一天一道LeetCode系列 (一)题目 Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example, [1,1,2] have the following unique permutations: [1,1,2], [1,2,1], and [2,1,1]. (二)解题 求全排列数.具体思路可以参考[一天一道LeetCode]#…

一天一道LeetCode系列 (一)题目 Given a collection of distinct numbers, return all possible permutations. For example, [1,2,3] have the following permutations: [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1]. (二)解题 求全排列数.具体思路可以参考[一天一道LeetCode]#31. Next…

根据issac3 用Java总结了backtracking template, 我用他的方法改成了Python. 以下为template. def backtrack(ans, temp, nums, start): # 可能有start, 也可能没有 if len(temp) == len(nums): ans.append(temp) else: for i in range(start, len(nums)): if nums[i] not in temp: backtrack(ans,…