《leetCode》:Rotate Array

题目

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.

思路一

此题在《剑指Offer》上面遇到过,而且解题思路也还记得,如下:
将数组中前面(n-k)个元素逆序,以及将数组后面的k个元素 逆序,最后将整体逆序即可。

/*
思路:将数组中前面(n-k)个元素逆序,以及将数组后面的k个元素 逆序
最后将整体逆序即可。 
*/
void swap(int *a,int *b){
    int temp=*a;
    *a=*b;
    *b=temp;
}
//函数功能:将数组nums进行逆序 
void reverse(int *nums,int numsSize){
    if(nums==NULL||numsSize<1){
        return ;
    } 
    int begin=0;
    int end=numsSize-1;
    while(begin<end){
        swap(&nums[begin],&nums[end]);
        begin++;
        end--;
    }
}
void rotate(int* nums, int numsSize, int k) {
    if(nums==NULL||numsSize<1||k<0){
        return;
    } 
    k=k%numsSize;
    reverse(nums,numsSize-k);
    reverse(nums+numsSize-k,k);
    reverse(nums,numsSize); 
}

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