leetcode Sort Colors
计数排序 注: 题目的要求是将 A 数组重新排列成有序, 而不是将排序的序列输出
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.
Note:
You are not suppose to use the library‘s sort function for this problem.
class Solution { public: void sortColors(int A[], int n) { int num1 = 0, num2 = 0, num3 = 0; for (int i = 0; i < n; i++) { if (A[i] == 0) num1++; else if (A[i] == 1) num2++; else if (A[i] == 2) num3++; } int sub = 0; for (int i = 0; i < num1; i++) { A[sub++] = 0; } for (int i = 0; i < num2; i++) { A[sub++] = 1; } for (int i = 0; i < num3; i++) { A[sub++] = 2; } } };
