LeetCode 189. Rotate Array

最新推荐文章于 2024-10-06 14:52:46 发布

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本文介绍了如何将数组向右旋转指定步数，并提供了两种不同的解决方案。第一种方法通过原地反转数组，实现高效旋转；第二种方法利用了数组推移特性进行操作。这两种方法都遵循了题目的要求，即至少提供三种不同的解决思路。

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].

Note:
Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem.

Have two methods there, nothing special

#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

void rotate(vector<int>& nums, int k) {
    k = k % nums.size();  // this is the only place needs attention.
    reverse(nums.begin(), nums.end());
    reverse(nums.begin(), nums.begin() + k);  // in-place
    reverse(nums.begin() + k, nums.end());
}

void rotateII(vector<int>& nums, int k) {
    int size = nums.size();
    for(int i = 0; i < size - k; ++i) {
        nums.push_back(nums[i]);
    }
    vector<int> newnums(nums.begin() + size - k, nums.end());
    nums = newnums;
}

int main(void) {
    vector<int> nums;
    nums.push_back(1);
    nums.push_back(2);
    nums.push_back(3);
    nums.push_back(4);
    nums.push_back(5);
    nums.push_back(6);
    nums.push_back(7);
    rotateII(nums, 3);
    for(int i = 0; i < nums.size(); ++i) {
        cout << nums[i] << endl;
    }
    cout << endl;
}