Find Peak Element

A peak element is an element, which is greater than its neighbors.

Given an input array where num[i] ≠ num[i+1] , the find a peak element and return its index.

The array may be contain multiple peaks, in this case return the index to any one of the peaks is fine.

May imagine num[-1] = num[n] = -∞ .

For example, in array [1, 2, 3, 1] , 3 is a peak element and your function should return the index number 2.

Note:

Your solution should is in logarithmic complexity.

C + + Implementation code:

#include <iostream>#include<vector>#include<climits>using namespacestd;classSolution { Public:    intFindpeakelement (Constvector<int> &num) {        if(Num.empty ())return-1; if(num.size () = =1|| num[0]>num[1])            return 0; intI=1; intn=num.size ();  while(i<n-1)        {            if(num[i]>num[i-1]&&num[i]>num[i+1])                returni; I++; }        if(i==n-1&&num[i]>num[i-1])            returni; return-1; }};intMain () {solution S; Vector<int> vec={1,2}; cout<<s.findpeakelement (VEC) <<Endl;}

Find Peak Element