Given a permutation which may contain repeated numbers, find its index in all the permutations of these numbers, which are ordered in lexicographical order. The index begins at 1. Have you met this question in a real interview? Yes Example Given the…

题目:http://www.lintcode.com/zh-cn/problem/permutation-index/ 排列序号 给出一个不含重复数字的排列,求这些数字的所有排列按字典序排序后该排列的编号.其中,编号从1开始. 样例 例如,排列[1,2,4]是第1个排列. 思路: 1.直接暴力,利用c++中<algorithm>中的next_permutation()方法不断的寻找下一个全排列,直到相等为止! 2.首先观察一个全排列, 例如:95412 = X a.题目转换成按照字典序,这个全…

Given a permutation which contains no repeated number, find its index in all the permutations of these numbers, which are ordered in lexicographical order. The index begins at 1. Example Given [1,2,4], return 1. 分析:http://www.cnblogs.com/EdwardLiu/p/…

LintCode 197. Permutation Index (Easy) LintCode 198. Permutation Index II (Medium) 感觉这两道题主要考察计算排列组合的能力. Permutation Index 举例: 123 -> 1 132 -> 2 213 -> 3 231 -> 4 312 -> 5 321 -> 6 以321为例进行分析: 首先考虑第一位3: 3右边比3小的数字有两个(1和2), 所以以1和2为首位的数字排在3x…

题目: 排列序号 给出一个不含重复数字的排列,求这些数字的所有排列按字典序排序后该排列的编号.其中,编号从1开始. 样例 例如,排列[1,2,4]是第1个排列. 解题: 这个题目感觉很坑的.感觉这只有求出所有的排列,然后找出其对应的下标,但是怎么求出排列,在做Project Euler 时候碰到过,但是现在我又不会写了,那时候毕竟是抄别人的程序的.在geekviewpoint看到一种很厉害的解法,不需要求所有的排列,直接根据给的数组进行求解. 思路: 1.对于四位数:4213 = 4*100+2…

Description Given a permutation which contains no repeated number, find its index in all the permutations of these numbers, which are ordered in lexicographical order. The index begins at 1. Example Given [1,2,4], return 1. 解题:至今仍然不理解这个“字典中的顺序”是什么意思,…

Sort Colors II 原题链接: http://lintcode.com/zh-cn/problem/sort-colors-ii/# Given an array of n objects with k different colors (numbered from 1 to k), sort them so that objects of the same color are adjacent, with the colors in the order 1, 2, ... k. 注意…

Given a permutation which contains no repeated number, find its index in all the permutations of these numbers, which are ordered in lexicographical order. The index begins at 1. Example Given [1,2,4], return 1. class Solution { public: /** * @param…

Palindrome Permutation I Given a string, determine if a permutation of the string could form a palindrome. For example,"code" -> False, "aab" -> True, "carerac" -> True. Hint: Consider the palindromes of odd vs even…

Palindrome Permutation Given a string, determine if a permutation of the string could form a palindrome. For example,"code" -> False, "aab" -> True, "carerac" -> True. Hint: Consider the palindromes of odd vs even le…