LeetCode -- Find Peak Element

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public class Solution {
    public int FindPeakElement(int[] nums) {
        if(nums.Length == 0){
			return -1;
		}
		if(nums.Length == 1){
			return 0;
		}
		if(nums.Length == 2){
			return nums[0] > nums[1] ? 0 : 1;
		}
		if(nums[nums.Length - 1] > nums[nums.Length - 2]){
			return nums.Length -1;
		}
		if(nums[0] > nums[1]){
			return 0;
		}
		
		var l = 0;
		var r = nums.Length - 1;
		while(l < r - 1){
			var m = (l + r) / 2;
			
			if(nums[m] > nums[m-1] && nums[m] > nums[m+1]){
				return m;
			}
			else if(nums[m] > nums[m-1] && nums[m] < nums[m+1]){ // increasing , go right
				l = m;
			}
			else { // decreasing , go left
				r = m;
			}
		}
		
		return -1;
    }
}

LeetCode -- Find Peak Element

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原文地址：http://blog.csdn.net/lan_liang/article/details/49055175