Added Implementation of Peak Element Program

search/FindPeakElement.cpp

@@ -0,0 +1,115 @@
+/**
+ * \file FindPeakElement.cpp
+ * \brief [Find peak element in Array]
+ * @author Unknown author
+ * @author https://github.com/AbhineshJha 
+*/
+
+#include <cassert>   // for assert
+#include <iostream>  // for IO operations
+
+/**
+ * \brief [Algorithm implementation for finding a peak element]
+ * \param [in] array array to search in
+ * \param [in] size length of array
+ * \returns index of a peak element in the array
+ * \returns -1 if no peak element is found
+ */
+int FindPeakElement(int *array, int size) {
+    if (size == 0) {
+        return -1; // No elements in the array
+    }
+
+    if (size == 1) {
+        return 0;  // Single element is a peak
+    }
+
+    // Check the first element
+    if (array[0] >= array[1]) {
+        return 0;
+    }
+
+    // Check the last element
+    if (array[size - 1] >= array[size - 2]) {
+        return size - 1;
+    }
+
+    // Check elements in the middle
+    for (int i = 1; i < size - 1; ++i) {
+        if (array[i] >= array[i - 1] && array[i] >= array[i + 1]) {
+            return i;
+        }
+    }
+
+    // If no peak is found, return -1
+    return -1;
+}
+
+/**
+ * @brief Self-test implementations
+ * @returns void
+ */
+static void tests() {
+    int size = 6;
+    int array[] = {1, 3, 20, 4, 1, 0};
+    assert(FindPeakElement(array, size) == 2);
+
+    size = 5;
+    int array2[] = {5, 10, 20, 15, 5};
+    assert(FindPeakElement(array2, size) == 2);
+
+    size = 4;
+    int array3[] = {10, 20, 15, 2};
+    assert(FindPeakElement(array3, size) == 1);
+
+    size = 1;
+    int array4[] = {5};
+    assert(FindPeakElement(array4, size) == 0);
+
+    std::cout << "All tests have successfully passed!" << std::endl;
+}
+
+/**
+ * @brief Main function
+ * @returns 0 on exit
+ */
+int main() {
+    int mode = 0;
+
+    std::cout << "Choose mode\n";
+    std::cout << "Self-test mode (1), interactive mode (2): ";
+
+    std::cin >> mode;
+
+    if (mode == 2) {
+        int size = 0;
+        std::cout << "\nEnter the size of the array [in range 1-30 ]: ";
+        std::cin >> size;
+
+        while (size <= 0 || size > 30) {
+            std::cout << "Size can only be 1-30. Please choose another value: ";
+            std::cin >> size;
+        }
+
+        int *array = new int[size];
+        int key = 0;
+
+        // Input for the array elements
+        std::cout << "Enter the array of " << size << " numbers: ";
+        for (int i = 0; i < size; i++) {
+            std::cin >> array[i];
+        }
+
+        int peakIndex = FindPeakElement(array, size);
+        if (peakIndex != -1) {
+            std::cout << "Peak element is " << array[peakIndex] << " at index: " << peakIndex << std::endl;
+        } else {
+            std::cout << "No peak element found in the array." << std::endl;
+        }
+
+        delete[] array;
+    } else {
+        tests();  // run self-test implementations
+    }
+    return 0;
+}