Added kadane's algorithm

kadane's_algorithm.cpp

@@ -0,0 +1,33 @@
+// kadane's algorithm
+
+#include <bits/stdc++.h>
+using namespace std;
+
+int max_array_sum(int ar[],int a){
+
+    int till_cur_sum=0 , total_sum=INT_MIN , max_element=INT_MIN;
+        for(int j=0;j<a;j++){
+            till_cur_sum = till_cur_sum + ar[j];
+            total_sum = max(till_cur_sum,total_sum);
+          //  max_element= max(max_element,ar[j]);
+            if(till_cur_sum<0){
+                till_cur_sum=0;
+            }
+        }
+        if(total_sum==0){
+          total_sum = max_element;
+        }
+     return total_sum;
+}
+
+int main(){
+    int n;
+    cin>>n;
+    int arr[n];
+
+    for(int i=0;i<n;i++){
+        cin>>arr[i];
+    }
+    cout<<" Maximum subarray sum : "<< max_array_sum(arr,n); 
+    return 0;
+}