From e41000ac79b46bae3c1f76baf4ddaed95ef3757c Mon Sep 17 00:00:00 2001
From: yash7047 <yashjaiswal895@gmail.com>
Date: Mon, 5 Oct 2020 09:33:36 +0530
Subject: [PATCH] maximum_circular_subarray_sum

---
 maximum_circular_sum.txt | 57 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 maximum_circular_sum.txt

diff --git a/maximum_circular_sum.txt b/maximum_circular_sum.txt
new file mode 100644
index 0000000..4cbe9eb
--- /dev/null
+++ b/maximum_circular_sum.txt
@@ -0,0 +1,57 @@
+/* MY COMPETITIVE CODING TEMPLATE */
+#include<bits/stdc++.h>
+using namespace std;
+#define ll long long int
+#define fastio ios_base::sync_with_stdio(false);cin.tie(NULL);
+#define pb push_back
+#define pp pair<ll,ll>
+#define all(v) (v).begin(),(v).end()
+#define sz(v) (ll)(v).size()
+#define F first 
+#define S second 
+#define lc "\n"
+ll MAX=1e18 , MIN=-1e18 , MOD=1000000007;
+void YJ()
+{
+#ifndef ONLINE_JUDGE
+    freopen("input.txt","r",stdin);
+    freopen("output.txt","w",stdout);
+#endif
+}
+
+/*  CODE STARTS HERE */
+
+/* KADANE'S ALGORITHM */
+int kadane(int arr[],int n) 
+{ 
+    int max_so_far=0,sum=0; 
+    for(int i=0;i<n;i++) 
+    { 
+        sum+=arr[i]; 
+        if(sum<0) sum=0; 
+        if(max_so_far<sum) max_so_far=sum; 
+    } 
+    return max_so_far; 
+} 
+
+int maxCircularSum(int arr[],int n) 
+{ 
+    int max_sum=kadane(arr,n); 
+    int s=0,i; 
+    for(i=0;i<n;i++) 
+    { 
+        s+=arr[i]; 
+        arr[i]=-arr[i]; 
+    } 
+    s=s+kadane(arr,n);  
+    return max(s,max_sum); 
+} 
+
+int main() 
+{
+    YJ(); fastio
+    int n,i; cin>>n; int arr[n];
+    for(i=0;i<n;i++) cin>>arr[i];
+    cout<<"Maximum circular sum is "<<maxCircularSum(arr,n)<<lc; 
+    return 0;
+}
\ No newline at end of file