java的 三目运算符

Question

public int wiggleMaxLength(int[] nums) {

        if(nums.length < 2) return nums.length;

        int len = nums.length, ans = len, flag = 0;

        for(int i = 1; i < len; i++)

        {

            if(nums[i]-nums[i-1] == 0) ans--;

            else if(nums[i]-nums[i-1]>0) flag==1? ans--:flag=1;

            else if(nums[i]-nums[i-1]<0) flag==-1?ans--:flag=-1;

        }

        return ans;

    }

求问for循环里面的两句三目运算符为什么不对？怎么写才对？

Answer 1

public int wiggleMaxLength(int[] nums) {&nbsp; &nbsp; &nbsp; &nbsp; if (nums.length < 2) return nums.length;&nbsp; &nbsp; &nbsp; &nbsp; int len = nums.length, ans = len, flag = 0;&nbsp; &nbsp; &nbsp; &nbsp; for (int i = 1; i < len; i++) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (nums[i] - nums[i - 1] == 0) ans--;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; else if (nums[i] - nums[i - 1] > 0) flag = flag == 1 ? ans-- : 1;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; else if (nums[i] - nums[i - 1] < 0) flag = flag == -1 ? ans-- : -1;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; return ans;&nbsp; &nbsp; }答案跟题主的需求有些出入，这里的确不太适合用三元。

Answer 2

不关对错，这地方就不应该用三目，逻辑这么多，别人都看不懂你的代码大多数的情况下，就用if else吧，注释方便，比较清晰明了，语法糖不用也罢

Answer 3

这里不适合使用三元运算符public int wiggleMaxLength(int[] nums) {&nbsp; &nbsp; if (nums.length < 2) return nums.length;&nbsp; &nbsp; int len = nums.length, ans = len, flag = 0;&nbsp; &nbsp; for (int i = 1; i < len; i++) {&nbsp; &nbsp; &nbsp; &nbsp; if (nums[i] - nums[i - 1] == 0) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ans--;&nbsp; &nbsp; &nbsp; &nbsp; } else if (nums[i] - nums[i - 1] > 0) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (flag == 1) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ans--;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } else {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; flag = 1;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; } else if (nums[i] - nums[i - 1] < 0) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (flag == -1) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ans--;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } else {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; flag = -1;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }&nbsp; &nbsp; return ans;}