Sort Colors Problem
Description
LeetCode Problem 75.
Given an array nums 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.
We will use the integers 0, 1, and 2 to represent the color red, white, and blue, respectively.
You must solve this problem without using the library’s sort function.
Example 1:
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Input: nums = [2,0,2,1,1,0]
Output: [0,0,1,1,2,2]
Example 2:
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Input: nums = [2,0,1]
Output: [0,1,2]
Example 3:
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Input: nums = [0]
Output: [0]
Example 4:
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Input: nums = [1]
Output: [1]
Constraints:
- n == nums.length
- 1 <= n <= 300
- nums[i] is 0, 1, or 2.
Sample C++ Code
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class Solution {
public:
void sortColors(vector<int>& nums) {
int p0 = 0, p2 = nums.size()-1;
int curr = 0, tmp;
while (curr <= p2) {
if (nums[curr] == 0) {
tmp = nums[curr];
nums[curr] = nums[p0];
nums[p0] = tmp;
curr ++;
p0 ++;
} else if (nums[curr] == 2) {
tmp = nums[curr];
nums[curr] = nums[p2];
nums[p2] = tmp;
p2 --;
} else {
curr ++;
}
}
return;
}
};