[Medium] Title: 162. Find Peak Element - LeetCode

Author: JinHyung-dev

LeetCode/Medium/162. Find Peak Element/Find Peak Element.java

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+class Solution {
+    public int findPeakElement(int[] nums) {
+        if (nums.length == 1) return 0;
+        if (nums.length == 2) return nums[0] > nums[1] ? 0 : 1;
+
+        int startIdx = 0; int endIdx = nums.length - 1;
+
+        while(startIdx < endIdx) {
+
+            int midIdx = startIdx + (endIdx- startIdx) / 2;
+
+            if(nums[midIdx] < nums[midIdx + 1]) {
+                startIdx = midIdx + 1;
+            } else {
+                endIdx = midIdx;
+            }
+        }
+        return startIdx;
+    }
+}

LeetCode/Medium/162. Find Peak Element/README.md

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+# [Medium] 162. Find Peak Element
+
+[문제 링크](https://leetcode.com/problems/find-peak-element/)
+
+### 문제 설명
+A peak element is an element that is strictly greater than its neighbors.
+
+Given a**0-indexed**integer array`nums`, find a peak element, and return its index. If the array contains multiple peaks, return the index to**any of the peaks**.
+
+You may imagine that`nums[-1] = nums[n] = -∞`. In other words, an element is always considered to be strictly greater than a neighbor that is outside the array.
+
+You must write an algorithm that runs in`O(log n)`time.
+
+**Example 1:**
+
+```
+Input: nums = [1,2,3,1]
+Output: 2
+```
+
+Explanation: 3 is a peak element and your function should return the index number 2.
+
+**Example 2:**
+
+```
+Input: nums = [1,2,1,3,5,6,4]
+Output: 5
+```
+
+Explanation: Your function can return either index number 1 where the peak element is 2, or index number 5 where the peak element is 6.
+
+**Constraints:**
+
+- `1 <= nums.length <= 1000`
+- `231 <= nums[i] <= 231 - 1`
+- `nums[i] != nums[i + 1]`for all valid`i`.