658. 找到 K 个最接近的元素

leetcode链接：
https://leetcode.cn/problems/find-k-closest-elements/description/

方案一——未完成测试

没完成所有相关测试

int left = 0,
	right = arr.length - 1,
	mid = 0,
	flag = 0,
	flag_1 = 0,
	arr_size = arr.length - 1;
List<Integer> result = new ArrayList<>();

while (left <= right) {
	mid = left + (right - left) / 2;
	if (arr[mid] > x) {
		right =  mid - 1;
	} else if (arr[mid] == x) {
		break;
	} else {
		left =  mid + 1;
	}
}


right = mid - k / 2;
if (right < 0) {
	flag = 1;
	right = 0;
}
if ((right + k) > arr_size) {
	flag = 1;
	right = arr_size - k + 1;
	if (Math.abs(arr[right] - x) <= Math.abs(arr[right + k -1] - x)) {
		right--;
	}

}


while (flag == 0) {
	if (right < 0 || (right + k) > arr_size || flag_1 > 1 || Math.abs(arr[right] - x) == Math.abs(arr[right + k -1] - x)) {
		break;
	}
	flag_1 = 0;
	if (Math.abs(arr[right] - x) > Math.abs(arr[right + k -1] - x)) {
		flag_1++;
		right++;
	}
	if (Math.abs(arr[right] - x) < Math.abs(arr[right + k -1] - x)) {
		flag_1++;
		right--;
	}
}

while (true) {
	if (right <= 0) {
		break;
	}
	if (arr[right] != arr[--right]) {
		right++;
		break;
	}
}

if (right < 0)
	right = 0;

for (int i = 0; i < k; i++) {
	result.add(arr[right + i]);
}

return result;

结果

Wrong Answer

• 47/66 cases passed (N/A)

Testcase

[1,10,15,25,35,45,50,59]
1
30

Answer

[35]

Expected Answer

[25]

分析

知识没有进行灵活应用

方案二

学习题解相关思想，重新整理思路：
https://leetcode.cn/problems/find-k-closest-elements/solution/zhao-dao-k-ge-zui-jie-jin-de-yuan-su-by-ekwtd/
二分法+双指针

int left = 0,
	right = arr.length - 1,
	mid = 0;
List<Integer> result = new ArrayList<>();
while (left < right) {
	mid = left + (right - left) / 2;
	if (arr[mid] >= x) {
		right =  mid;
	} else {
		left =  mid + 1;
	}
}

left = right - 1;
while (k-- > 0) {
	if (left < 0) {
		right++;
	} else if (right >= arr.length) {
		left--;
	} else if (x - arr[left] <= arr[right] - x) {
		left--;
	} else {
		right++;
	}
}

for (int i = left + 1; i < right; i++) {
	result.add(arr[i]);
}

return result;

结果

• 66/66 cases passed (3 ms)
• Your runtime beats 99.62 % of java submissions
• Your memory usage beats 79.79 % of java submissions (43.1 MB)

较为详细的解题思路

https://leetcode.cn/problems/find-k-closest-elements/solution/pai-chu-fa-shuang-zhi-zhen-er-fen-fa-python-dai-ma/