public class Solution {    public int findPeakElement(int[] num) {        // binary search http://siddontang.gitbooks.io/leetcode-solution/content/array/find_peak_element.html                if(num==null || num.length ==0) return -1;        if (num.length==1)            return 0;        int left=0, right=num.length-1;        int mid=left+(right-left)/2;                while(left<= right){            mid=left+(right-left)/2;                         //if(mid == 0 || num[mid]>=num[mid-1] &&num[mid]>=num[mid+1] || mid == num.length-1 ) return mid;            // if((mid == 0 || num[mid]>=num[mid-1] ) && (num[mid]>=num[mid+1] || mid == num.length-1) ) return mid; // java 里不能存在不存在的index 索引吧，比如num[-1]                        if((mid==0 && num[mid]>num[mid+1]) || (mid==num.length-1 && num[mid] > num[mid-1]) || ( num[mid]>num[mid+1] && num[mid] > num[mid-1])) return mid;                        if(mid>0 && num[mid]

leetcode 把输入的int[]改为list，非常不好用，只好贴一些之前的code