LeetCode: Sort Colors
没写出来,看到网上一个非常好的code,不过这个code不太容易想出来
1 class Solution { 2 public: 3 void sortColors(int A[], int n) { 4 // Start typing your C/C++ solution below 5 // DO NOT write int main() function 6 int pos[3] = {}; 7 for (int i = 0; i < n; i++) { 8 int cur = A[i]; 9 for (int j = 2; j >= cur; j--) { 10 A[pos[j]] = j; 11 pos[j]++; 12 } 13 } 14 } 15 };
下面是一个比较容易想出来的code。
1 class Solution { 2 public: 3 void sortColors(int A[], int n) { 4 // Start typing your C/C++ solution below 5 // DO NOT write int main() function 6 int left = 0; 7 int right = n-1; 8 int mid = n-1; 9 while (left <= mid) { 10 if (A[left] == 2) { 11 int tmp = A[right]; 12 A[right] = A[left]; 13 A[left] = tmp; 14 right--; 15 if (right < mid) mid = right; 16 } 17 if (A[left] == 1) { 18 int tmp = A[mid]; 19 A[mid] = A[left]; 20 A[left] = tmp; 21 mid--; 22 } 23 if (A[left] == 0) left++; 24 } 25 } 26 };
C#
1 public class Solution { 2 public void SortColors(int[] nums) { 3 int left = 0, right = nums.Length - 1, mid = nums.Length - 1; 4 while (left <= mid) { 5 if (nums[left] == 2) { 6 int tmp = nums[right]; 7 nums[right] = nums[left]; 8 nums[left] = tmp; 9 right--; 10 if (right < mid) mid = right; 11 } 12 if (nums[left] == 1) { 13 int tmp = nums[mid]; 14 nums[mid] = nums[left]; 15 nums[left] = tmp; 16 mid--; 17 } 18 if (nums[left] == 0) left++; 19 } 20 } 21 }