Longest increasing subsequence

Author: coderick14

LIS.cpp

@@ -0,0 +1,45 @@
+#include <bits/stdc++.h>
+#define ll long long
+using namespace std;
+
+void printLIS(vector<ll> &a, vector<ll> &prev, int pos) {
+    if(pos<0)
+        return;
+    printLIS(a, prev, prev[pos]);
+    cout<<a[pos]<<" ";
+}
+
+void LIS(vector<ll> &a) {
+    int i,j,maxim = 0,n = a.size();
+    vector<ll> LIS(n,1);
+    vector<ll> prev(n,-1);
+    for(i=0; i<n; i++) {
+        for(j=0; j<i; j++) {
+            if(a[i] > a[j] && LIS[i] < LIS[j]+1) {
+                LIS[i] = LIS[j] + 1;
+                prev[i] = j;
+            }
+        }
+    }
+    int pos = 0;
+    for(i=0; i<n; i++) {
+        if(LIS[i] > maxim) {
+            maxim = LIS[i];
+            pos = i;
+        }
+    }
+    cout<<"Length of LIS = "<<maxim<<endl;
+    printLIS(a,prev,pos);
+    cout<<endl;
+}
+
+int main() {
+    ll i,n;
+    cin>>n;
+    vector<ll> a(n);
+    for(i=0; i<n; i++) {
+        cin>>a[i];
+    }
+    LIS(a);
+    return 0;
+}