Longest Increasing Subsequence code added in C++

Author: Nilaycb

LIS.cpp

@@ -0,0 +1,62 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+int main()
+{
+ int n, i, j, l, max_indx;
+ vector<int> LIS;
+
+ cout << "Enter the length of Series: ";
+ cin >> n;
+
+ int arr[n];
+
+ cout << "Enter values of the Series: ";
+ for(i=0; i<n; i++)
+ {
+ cin >> arr[i];
+ }
+ cout << endl;
+
+ int len[n], prev[n];
+ fill_n(len, n, 1);
+ fill_n(prev, n, -1);
+
+ for(i=0; i<n; i++)
+ {
+ for(j=i+1; j<n; j++)
+ {
+ if(arr[i] < arr[j]) // for LDS change this condition to arr[i] > arr[j]
+ {
+ prev[j] = (len[i]+1 >= len[j]) ? i : prev[j];
+ len[j] = max(len[j], len[i]+1);
+ }
+ }
+ }
+
+ l = *max_element(len, len+n);
+ max_indx = distance(len, max_element(len, len+n));
+
+ int v = max_indx;
+ for(i=0; i<l; i++)
+ {
+ LIS.push_back(arr[v]);
+ v = prev[v];
+ }
+
+ reverse(LIS.begin(), LIS.end());
+
+ cout << "Length of LIS = " << l << endl;
+ cout << "The LIS is ";
+ for(i=0; i<LIS.size(); i++)
+ {
+ cout << LIS[i];
+
+ if(i != LIS.size()-1)
+ cout << ", ";
+ else
+ cout << endl;
+ }
+
+ return 0;
+}