Leetcode75 颜色分类

　　思路比较简单，可以采用计数法，不知为何会被分为中等。

　　JAVA：

public final void sortColors(int[] nums) {
        int num0 = 0;
        int num1 = 0;
        int num2 = 0;
        for (int i = 0; i < nums.length; i++) {
            int curr = nums[i];
            if (curr == 0) {
                num0++;
            } else if (curr == 1) {
                num1++;
            } else {
                num2++;
            }
        }
        build(0, num0, 0, nums);
        build(num0, num0 + num1, 1, nums);
        build(num0 + num1, nums.length, 2, nums);
    }

    private final void build(int begin, int end, int target, int[] nums) {
        for (int i = begin; i < end; i++) {
            nums[i] = target;
        }
    }

　　JS：

var sortColors = function (nums) {
    let num0 = 0;
    let num1 = 0;
    let num2 = 0;
    for (let i = 0; i < nums.length; i++) {
        if (nums[i] == 0) {
            num0++;
        } else if (nums[i] == 1) {
            num1++;
        } else {
            num2++;
        }
    }
    build(0, num0, 0, nums);
    build(num0, num0 + num1, 1, nums);
    build(num0 + num1, nums.length, 2, nums);
};

var build = function (begin, end, target, arr) {
    for (let i = begin; i < end; i++) {
        arr[i] = target;
    }
}