From ff8bb607bb7cc08127be79aab0efd853e3f86a5b Mon Sep 17 00:00:00 2001
From: x-samx <satyamshukla0000@gmail.com>
Date: Sun, 27 Oct 2019 00:37:03 +0530
Subject: [PATCH] Added longest bitonic subsequence

---
 Longest_Bitonic_Subsequence/lbs.cpp | 42 +++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 Longest_Bitonic_Subsequence/lbs.cpp

diff --git a/Longest_Bitonic_Subsequence/lbs.cpp b/Longest_Bitonic_Subsequence/lbs.cpp
new file mode 100644
index 0000000..0d4082a
--- /dev/null
+++ b/Longest_Bitonic_Subsequence/lbs.cpp
@@ -0,0 +1,42 @@
+
+#include<bits/stdc++.h>
+using namespace std;
+
+int main() 
+{
+    vector<int> A{1,11,2,10,4,5,2};
+    int n = A.size();
+    if(n < 1)
+    return 0;
+    int lis[n];
+    int lds[n];
+    lis[0] = 1;
+    lds[n-1] = 1;
+    for(int i = 1 ; i < A.size() ; ++i)
+    {
+        lis[i] = 1;
+        for(int j = 0 ; j < i ; ++j)
+        {
+            if(A[i] > A[j] && lis[i] < lis[j] + 1)
+            lis[i] = lis[i] + 1;
+        }
+    }
+    for(int i = n-2 ; i >= 0 ; --i)
+    {
+        lds[i] = 1;
+        for(int j = n-1 ; j > i ; --j)
+        {
+            if(A[i] > A[j] && lds[i] < lds[j] + 1)
+            lds[i] = lds[i] + 1;
+        }
+    }
+    int max = lis[0] + lds[0] - 1;
+    for(int i= 0 ; i < n ; ++i)
+    {
+        if(lis[i] + lds[i] - 1 > max)
+        max = lis[i] + lds[i] - 1;
+    }
+    
+    cout << "\nLength of longest bitonic subsequence : " << max;
+    return 0;
+}
\ No newline at end of file