LeetCode 75
Find Peak Element
- Problem
- LC 162
- Topic
- Binary Search
- File
- official75_LC162FindPeakElement.java
- Path
- pkg5leetcode/official75/official75_LC162FindPeakElement.java
- Package
- pkg5leetcode.official75
- Command
- java pkg5leetcode/official75/official75_LC162FindPeakElement.java
- Approach
- Binary search on slope compare mid and mid+1.
- Complexity
- Time O(log n), Space O(1)
There is no in-browser runner. This is the file from the curriculum, unchanged.
1package pkg5leetcode.official75;2 3/*4 * Find Peak Element | LC 1625 * APPROACH: Binary search on slope compare mid and mid+1.6 * COMPLEXITY: Time O(log n), Space O(1)7 */8public class official75_LC162FindPeakElement {9 static int findPeakElement(int[] nums) {10 int lo = 0, hi = nums.length - 1;11 while (lo < hi) {12 int mid = lo + (hi - lo) / 2;13 if (nums[mid] < nums[mid + 1]) lo = mid + 1;14 else hi = mid;15 }16 return lo;17 }18 19 public static void main(String[] args) {20 check(findPeakElement(new int[]{1,2,3,1}) == 2, "case1");21 check(findPeakElement(new int[]{1,2,1,3,5,6,4}) == 5, "case2");22 System.out.println("all tests passed");23 }24 25 static void check(boolean cond, String name) {26 if (!cond) throw new AssertionError("FAILED: " + name);27 System.out.println(" PASS " + name);28 }29}