Sort Colors

Given an array with n objects colored red, white or blue, sort them 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.

思路：可以先统计数组中含有０，１，２的个数。然后重修修改数组的元素即可

class Solution {
public:
void sortColors(vector<int>& nums) {
if(nums.size()<2)
return;
int sortRed=0;
int sortWhite=0;
int sortBlue=0;
for(int i=0;i<nums.size();i++)
{
if(nums[i]==0)
sortRed++;
else if(nums[i]==1)
sortWhite++;
else if(nums[i]==2)
sortBlue++;
}
int i=0;
while(sortRed)
{
nums[i++]=0;
sortRed--;
}
while(sortWhite)
{
nums[i++]=1;
sortWhite--;
}
while(sortBlue)
{
nums[i++]=2;
sortBlue--;
}
}

};