Kadane's Algorithm.cpp

algorithms/Greedy_Algorithms/Kadane's Algorithm.cpp

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+//Implemented in C++14
+
+#include <iostream>
+using namespace std;
+
+// Utility function to return maximum number present in given array
+int maximum(int arr[], int n)
+{
+	int res = arr[0];
+	for (int i = 1; i < n; i++)
+		res = max(res, arr[i]);
+
+	return res;
+}
+
+// Function to find contiguous sub-array with the largest sum
+// in given set of integers
+int kadane(int arr[], int n)
+{
+	// find maximum element present in given array
+	int max_num = maximum(arr, n);
+
+	// if array contains all negative values, return maximum element
+	if (max_num < 0)
+		return max_num;
+
+	// stores maximum sum sub-array found so far
+	int max_so_far = 0;
+
+	// stores maximum sum of sub-array ending at current position
+	int max_ending_here = 0;
+
+	// traverse the given array
+	for (int i = 0; i < n; i++)
+	{
+		// update maximum sum of sub-array "ending" at index i (by adding
+		// current element to maximum sum ending at previous index i-1)
+		max_ending_here = max_ending_here + arr[i];
+
+		// if maximum sum is negative, set it to 0 (which represents
+		// an empty sub-array)
+		max_ending_here = max(max_ending_here, 0);
+
+		// update result if current sub-array sum is found to be greater
+		max_so_far = max(max_so_far, max_ending_here);
+	}
+
+	return max_so_far;
+}
+
+int main()
+{
+	int n;
+  cout<<"Enter number of elements";
+  cin>>n;
+  int arr[n];
+  cout<<"\nEnter elements in array";
+  for(int i = 0;i < n;i++)
+  { cin>>arr[i]; }
+	cout << "The sum of contiguous sub-array with the largest sum is " <<
+			kadane(arr, n);
+
+	return 0;
+}