编程之美 2.17 数组循环移位

编程之美 2.17 数组循环移位

把一个含有N个元素的数组循环右移K位, 要求时间复杂度位O(N), 且只允许使用两个附加变量.

解法: 使用逆序方法, 分开两段求逆序, 再整体求逆序.

代码 (GCC 4.7.1):

/* * BeautyOfProgramming.cpp * *  Created on: 2013.11.7 *      Author: Caroline *      Time: O(N) */#include <iostream>#include <algorithm>#include <vector>#include <string>int main (void) {std::vector<std::string> sv ={"a", "b", "c", "d", "1", "2", "3", "4"};unsigned int n = 4;std::cout << "array : ";for(const auto s : sv)std::cout << s << " ";std::cout << std::endl;std::reverse(sv.begin(), sv.begin()+4);std::reverse(sv.begin()+4, sv.end());std::reverse(sv.begin(), sv.end());std::cout << "reverse (" << n <<") : ";for(const auto s : sv)std::cout << s << " ";std::cout << std::endl;return 0;}