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Find in Mountain Array.java
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class Solution {
public int findInMountainArray(int target, MountainArray mountainArr) {
int peak = findPeak(mountainArr);
int left =binary(0,peak,mountainArr,target,true);
if(left!=-1){
return left;
}
int right= binary(peak+1,mountainArr.length()-1,mountainArr, target,false);
return right;
}
static int findPeak(MountainArray mountainArr){
int start=0;
int end =mountainArr.length()-1;
while(start<end){
int mid=start+((end-start)/2);
if(mountainArr.get(mid)<mountainArr.get(mid+1)){
start=mid+1;
}else{
end=mid;
}
}
return start;
}
static int binary(int low, int high, MountainArray arr,int target, boolean left){
while(low<=high){
int mid=low+((high-low)/2);
if(target<arr.get(mid)){
if(left){
high=mid-1;
}else{
low=mid+1;
}
}else if(target>arr.get(mid)){
if(left){
low=mid+1;
}else{
high=mid-1;
}
}else{
return mid;
}
}
return -1;
}
}