Medium
Rotate Non Negative Elements — C++
Full explanation · Time O(n) · Space O(n)
// Time: O(n)
// Space: O(n)
// array
class Solution {
public:
vector<int> rotateElements(vector<int>& nums, int k) {
const auto& rotate = [](auto& nums, int64_t k) {
const int n = size(nums);
k %= n;
const auto& c = gcd(n, k);
for (int i = 0; i < c; ++i) {
for (int j = 1; j < n / c; ++j) {
swap(nums[i], nums[(((i - j * k) % n) + n) % n]);
}
}
};
vector<int> result;
result.reserve(size(nums));
for (const auto& x : nums) {
if (x >= 0) {
result.emplace_back(x);
}
}
if (empty(result)) {
return nums;
}
rotate(result, k);
for (int i = 0, j = 0; i < size(nums); ++i) {
if (nums[i] < 0) {
continue;
}
nums[i] = result[j++];
}
return nums;
}
};
// Time: O(n)
// Space: O(n)
// array
class Solution2 {
public:
vector<int> rotateElements(vector<int>& nums, int k) {
const auto& rotate = [](auto& nums, int k) {
k %= size(nums);
reverse(begin(nums), end(nums));
reverse(begin(nums), begin(nums) + (size(nums) - k));
reverse(begin(nums) + (size(nums) - k), end(nums));
};
vector<int> result;
result.reserve(size(nums));
for (const auto& x : nums) {
if (x >= 0) {
result.emplace_back(x);
}
}
if (empty(result)) {
return nums;
}
rotate(result, k);
for (int i = 0, j = 0; i < size(nums); ++i) {
if (nums[i] < 0) {
continue;
}
nums[i] = result[j++];
}
return nums;
}
};
// Time: O(n)
// Space: O(n)
// array
class Solution3 {
public:
vector<int> rotateElements(vector<int>& nums, int k) {
vector<int> result;
result.reserve(size(nums));
for (const auto& x : nums) {
if (x >= 0) {
result.emplace_back(x);
}
}
if (empty(result)) {
return nums;
}
k %= size(result);
rotate(begin(result), begin(result) + k, end(result));
for (int i = 0, j = 0; i < size(nums); ++i) {
if (nums[i] < 0) {
continue;
}
nums[i] = result[j++];
}
return nums;
}
};