Find in Mountain Array.cpp

class Solution {
public:
    int findInMountainArray(int target, MountainArray& mountainArr) {
        int length = mountainArr.length();
        int peakIndex = findPeakIndex(1, length - 2, mountainArr);
        int increasingIndex =
            binarySearch(0, peakIndex, target, mountainArr, false);
        if (mountainArr.get(increasingIndex) == target)
            return increasingIndex;
        int decreasingIndex =
            binarySearch(peakIndex + 1, length - 1, target, mountainArr, true);
        if (mountainArr.get(decreasingIndex) == target)
            return decreasingIndex;
        return -1;
    }
    int findPeakIndex(int low, int high, MountainArray& mountainArr) {
        while (low != high) {
            int mid = low + (high - low) / 2;
            if (mountainArr.get(mid) < mountainArr.get(mid + 1)) {
                low = mid + 1;
            } else {
                high = mid;
            }
        }
        return low;
    }
    int binarySearch(int low, int high, int target, MountainArray& mountainArr,
                     bool reversed) {
        while (low != high) {
            int mid = low + (high - low) / 2;
            if (reversed) {
                if (mountainArr.get(mid) > target)
                    low = mid + 1;
                else
                    high = mid;
            } else {
                if (mountainArr.get(mid) < target)
                    low = mid + 1;
                else
                    high = mid;
            }
        }
        return low;
    }
};