1053. Previous Permutation With One Swap https://leetcode.com/problems/previous-permutation-with-one-swap/ 题意:Given an array A of positive integers (not necessarily distinct), return the lexicographically largest permutation that is smaller than A, t…

题目如下: Given an array A of positive integers (not necessarily distinct), return the lexicographically largest permutation that is smaller than A, that can be made with one swap (A swap exchanges the positions of two numbers A[i] and A[j]).  If it cann…

Next Permutation Given a list of integers, which denote a permutation. Find the next permutation in ascending order. Notice The list may contains duplicate integers. Example For [1,3,2,3], the next permutation is [1,3,3,2] For [4,3,2,1], the next per…

A reverse version of the Dictionary algorithm :) If you AC-ed "Next Permutation II", copy it over and just reverse the conditions. class Solution { public: /** * @param nums: An array of integers * @return: An array of integers that's previous p…

Similar to next permutation, the steps as follow: 1) Find k in the increasing suffix such that nums[k] > nums[k+1], if there is no such element, the permutation is the smallest like [0, 1, 2,... n], reverse it, we can get the previous permutaton. 2)…

题目 上一个排列 给定一个整数数组来表示排列,找出其上一个排列. 样例 给出排列[1,3,2,3],其上一个排列是[1,2,3,3] 给出排列[1,2,3,4],其上一个排列是[4,3,2,1] 注意 排列中可能包含重复的整数 解题 排列的特征 123 的排列依次是:123.132.213.231.312.321 要点: 1.整体来说是升序的 2.对一个数而言,各位数字中,大的数字越靠后,这个数在排列的位置越靠前,同样,小的数字越靠前,这个数在排列的位置越靠前 参考1 参考2 上面说的方法好像都…

贪心基础 贪心(Greedy)常用于解决最优问题,以期通过某种策略获得一系列局部最优解.从而求得整体最优解. 贪心从局部最优角度考虑,只适用于具备无后效性的问题,即某个状态以前的过程不影响以后的状态.紧接下来的状态仅与当前状态有关.和分治.动态规划一样,贪心是一种思路,不是解决某类问题的具体方法. 应用贪心的关键,是甄别问题是否具备无后效性.找到获得局部最优的策略.有的问题比较浅显,例如一道找零钱的题目 LeetCode 860. Lemonade Change: // 860. Lemonad…

1051. Height Checker Students are asked to stand in non-decreasing order of heights for an annual photo. Return the minimum number of students not standing in the right positions.  (This is the number of students that must move in order for all stude…

Given a list of integers, which denote a permutation. Find the previous permutation in ascending order. Note The list may contains duplicate integers. Example For [1,3,2,3], the previous permutation is [1,2,3,3] For [1,2,3,4], the previous permutatio…

这是剑指offer数组中重复的数字那个题,直接使用的swap函数 class Solution { public: // Parameters: // numbers: an array of integers // length: the length of array numbers // duplication: (Output) the duplicated number in the array number // Return value: true if the input is…