51 lines
1.5 KiB
Java
51 lines
1.5 KiB
Java
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/*This is a Java Program to find peak element of an array. A peak element of an array is that element which is greater than its neighbors.
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The following program uses binary search approach to find a peak element. The time complexity of the following program is O (log n).*/
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/*
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* Java Program to Find the peak element of an array using
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* Binary Search approach
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*/
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import java.util.Scanner;
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public class PeakElement2
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{
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public static void main(String[] args)
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{
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Scanner scan = new Scanner(System.in);
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System.out.println("Enter size of array");
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int N = scan.nextInt();
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int[] arr = new int[ N ];
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/* Accept N elements */
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System.out.println("Enter "+ N +" elements");
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for (int i = 0; i < N; i++)
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arr[i] = scan.nextInt();
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/* Find Peak Elements */
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System.out.print("\nPeak Elements : ");
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peak(arr);
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System.out.println();
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}
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public static void peak(int[] arr)
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{
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peak(arr, 0, arr.length - 1);
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}
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public static void peak (int arr[], int low, int high)
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{
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int N = arr.length;
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if (high - low < 2)
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return;
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int mid = (low + high) / 2;
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if (arr[mid] > arr[mid - 1] && arr[mid] > arr[mid + 1])
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System.out.print(arr[mid] +" ");
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/* Recursively find other peak elements */
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peak (arr, low, mid);
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peak (arr, mid, high);
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}
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}
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/*
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Enter size of array
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8
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Enter 8 elements
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87 63 51 25 40 24 6 1
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Peak Elements : 40
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