77. Find a Peak Element
MediumBinary Search
Adjacent elements are different. A peak is an element strictly greater than its neighbours (outside the array counts as −∞). Print the index of the first peak (0-based).
Input format
Line 1: n Line 2: n integers
Output format
The index of the first peak.
Example 1
Input
4 1 2 3 1
Output
2
Example 2
Input
7 1 2 1 3 5 6 4
Output
1
Constraints
1 ≤ n ≤ 10⁵
Read input from standard input and print the answer to standard output. Your code is judged against 6 test cases, most of them hidden.
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