LeetCode - Find Peak Element

Find Peak Element

public int findPeakElement(int[] nums) {
        if(nums==null || nums.length==0) return -1;
        if(nums.length == 1) return 0;
        for(int i=0; i < nums.length; i++){
            if(i==0 && nums[i] > nums[i+1] || i==nums.length-1 && nums[i] > nums[i-1]) return i;
            if(nums[i] > nums[i+1] && nums[i] > nums[i-1]) return i;
        }
        return -1;
    }
//
public int findPeakElement(int[] num) {
        int left=0, right=num.length-1;
        while(left<right){
            int mid = (left+right)/2;
            int mid2 = mid+1;
            if(num[mid]>num[mid2]){
                right=mid;
            }
            else{
                left=mid+1;
            }
        }
        return left;
    }
//
public int findPeakElement(int[] num) {
        for(int i=1; i<num.length; i++){
            if(num[i] < num[i-1]){
                return i-1;
            }
        }
        return num.length-1;
    }
// binary search
public int findPeakElement(int[] nums) {
        if(nums==null || nums.length == 0) return -1;
        int left = 0, right = nums.length-1;
        while(left < right){
            int mid = (left + right) / 2;
            if(nums[mid] < nums[mid+1]) left = mid+1;
            else right = mid;
        }
        return left;
    }