LeetCode189——Rotate Array兩種解法(一種易讀,一種高效)
阿新 • • 發佈:2019-02-13
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.
[show hint]
Credits: Special thanks to @Freezen for adding this problem and creating all test cases.
難度係數:
容易
實現
void rotate(int nums[], int n, int k) {
int temp;
for (int step = 0; step < k; step++) {
temp = nums[n-1];
for (int i = n-1; i > 0; --i)
{
nums[i] = nums[i-1];
}
nums[0] = temp;
}
}
上面這個實現,很好理解,但是正如評論裡說的,執行效率不高。下面這個的效率有極大的提升:
void rotate(int nums[], int n, int k) { k = k % n; if (k == 0) return; int *temp = new int[n]; memcpy(temp, nums+(n-k), sizeof(int)*k); memcpy(temp+k, nums, sizeof(int)*(n-k)); memcpy(nums, temp, sizeof(int)*n); delete[] temp; }