// 852. Peak Index in a Mountain Array #include int peakIndexInMountainArray(int *arr, int arr_size) { int left = 1, right = arr_size - 1; while (left < right) { int mid = (left + right) / 2; if (arr[mid] < arr[mid + 1]) left = mid + 1; else right = mid; } return left; } int main() { int a1[] = {0, 1, 0}, a2[] = {0, 2, 1, 0}, a3[] = {0, 10, 5, 2}; printf("%d\n", peakIndexInMountainArray(a1, 3)); // expect: 1 printf("%d\n", peakIndexInMountainArray(a2, 4)); // expect: 1 printf("%d\n", peakIndexInMountainArray(a3, 4)); // expect: 1 }