标签：
Title:
Given an input string, reverse the string word by word.
For example,
Given s = "the sky is blue",
return "blue is sky the".
https://leetcode.com/problems/reverse-words-in-a-string/
思路：先将字符串全部逆转，在将每个单词逆转。具体实现，要注意空格，所以对字符串倒过来处理。
class Solution { public: void reverseWords(string &s) { string rs; for (int i = s.length()-1; i >= 0; ) { while (i >= 0 && s[i] == ‘ ‘) i--; if (i < 0) break; if (!rs.empty()) rs.push_back(‘ ‘); string t; while (i >= 0 && s[i] != ‘ ‘) t.push_back(s[i--]); reverse(t.begin(), t.end()); rs.append(t); } s = rs; } };
Rotate Array
Rotate an array of n elements to the right by k steps.
For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4].
https://leetcode.com/problems/rotate-array/
思路：一样，先将整个字符串反转，在对每个部分反转。另外注意k可能大于size。
class Solution { public: void rotate(vector<int>& nums, int k) { if ( k < 0) return ; int size = nums.size(); k = (k-1) % size + 1; reverse(nums,0,size-1); reverse(nums,0,k-1); reverse(nums,k,size-1); } void reverse(vector<int>& nums,int start, int end){ while (start < end){ nums[start] ^= nums[end]; nums[end] ^= nums[start]; nums[start++] ^= nums[end--]; } } };
LeetCode: Reverse Words in a String && Rotate Array
标签：
原文地址：http://www.cnblogs.com/yxzfscg/p/4556235.html
