(Leetcode 189) Rotate Array

Rotate an array of n elements to the right by K steps.

For example, with n = 7 and k = 3, the array is [1,2,3,4,5,6,7] rotated to [5,6,7,1,2,3,4] .

Topic:

Gives an array, n elements, moves the array to the right to move the k elements in a loop.

Ideas:

Note that the requirements of the topic are circular movement, so k can be any non-negative integer, but the number of array elements is n, so k=k%n.

A common idea is to:

1. Flip the entire array: a[0...n-1]; e.g. [7,6,5,4,3,2,1]

2, flip the array before K: a[0,k-1], such as [5,6,7,4,3,2,1]

3, flip the array after n-k: a[k,n-1], such as [5,6,7,1,2,3,4]

Similar applications: Flip all the words in a sentence, and the word content does not change.

Code:

classSolution { Public:    voidReverseintNums[],intIintj) {         while(i<j) {            inttmp=Nums[i]; Nums[i]=Nums[j]; NUMS[J]=tmp; I++; J--; }    }        voidRotateintNums[],intNintk) {k=k%N; if(k>=1&& n>1&& k<=N) {Reverse (nums,0, N-1); Reverse (Nums,0, K-1); Reverse (Nums,k,n-1); }    }};

(Leetcode 189) Rotate Array