颜色分类

/*

• @Author: sumBorn
• @Date: 2022-02-23 15:14:43
• @LastEditTime: 2022-02-23 19:02:07
• @Description: https://leetcode-cn.com/leetbook/read/all-about-array/x9wv2h/
  */

/**

• @description: 交换

• @param {*}

• @return {*}
  */
  public class Solution
  {
  public void SortColors(int[] nums)
  {
  for (var i = 0; i < nums.Length; i++)
  {
  for (var j = i + 1; j < nums.Length; j++)
  {
  if (nums[j] < nums[i])
  {
  Swap(nums, i, j);
  }
  }
  }
  }

  public void Swap(int[] nums, int i, int j)
  {
  int tmp = nums[i];
  nums[i] = nums[j];
  nums[j] = tmp;
  }
  }

/**

• @description: 双指针，为0左侧进1，为2右侧减1

• @param {*}

• @return {*}
  */
  public class Solution
  {
  public void SortColors(int[] nums)
  {
  if (nums.Length <= 1) return;

   int left = 0;
   int right = nums.Length - 1;
  
   for (var i = 0; i <= right; i++)
   {
       if (nums[i] == 0)
       {
           Swap(nums, left, i);
           left++;
       }
       else if (nums[i] == 2)
       {
           Swap(nums, right, i);
           right--;
           i--;
       }
   }
  

  }

  public void Swap(int[] nums, int i, int j)
  {
  int tmp = nums[i];
  nums[i] = nums[j];
  nums[j] = tmp;
  }
  }