标签：array HERE ret ted -o one while index color
算法描述：
Given an array with n objects colored red, white or blue, sort them in-place so that objects of the same color are adjacent, with the colors in the order red, white and blue.
Here, we will use the integers 0, 1, and 2 to represent the color red, white, and blue respectively.
Note: You are not suppose to use the library‘s sort function for this problem.
Example:
Input: [2,0,2,1,1,0] Output: [0,0,1,1,2,2]
Follow up:
解题思路：三种颜色，用三个指针区分。用中间的指针进行扫描，每次扫描完进行交换。如果值等于0，left和index指针进行交换，并且两个指针都右移动。如果值等于1，则只移动中间指针继续扫描。如果值等于2，将index和right进行交换，并右指针左移，index保持不变。因为index和right交换后，index所指的值是未知的，需要重新判断一下。
void sortColors(vector<int>& nums) { if(nums.size() ==0) return; int left = 0; int right = nums.size()-1; int index = 0; while(index <= right){ if(nums[index]==0){ swap(nums, left, index); left++; index++; } else if (nums[index]==1){ index++; } else{ swap(nums,index,right); right--; } } } void swap(vector<int>& nums, int da, int db){ int temp = nums[da]; nums[da] = nums[db]; nums[db] = temp; }
标签：array HERE ret ted -o one while index color
原文地址：https://www.cnblogs.com/nobodywang/p/10344760.html
