题解 | #寻找峰值#
寻找峰值
https://www.nowcoder.com/practice/fcf87540c4f347bcb4cf720b5b350c76
使用二分查找对比中间值与其左右的值的大小,从而进行进一步判断。特殊情况需要注意递增和递减数组。
import java.util.*; public class Solution { /** * 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可 * * * @param nums int整型一维数组 * @return int整型 */ public int findPeakElement (int[] nums) { // write code here if (nums.length == 1 || nums.length == 0) { return 0; } if (nums.length == 2) { return nums[0] > nums[1] ? 0 : 1; } int left = 0; int right = nums.length - 1; int mid = 0; while (left <= right) { mid = left + (right - left) / 2; System.out.println("kk " + mid); if (mid - 1 < 0 || mid + 1 > nums.length - 1) { return mid; } if ((nums[mid] > nums[mid - 1]) && (nums[mid] < nums[mid + 1])) { left = mid + 1; } else if ((nums[mid] < nums[mid - 1]) && (nums[mid] > nums[mid + 1])) { right = mid - 1; } else if ((nums[mid] < nums[mid - 1]) && (nums[mid] < nums[mid + 1])) { left = mid + 1; } else { break; } } return mid; } }