From 53c79b7ec60eeb65563d1986e8ba33ee2c7cc488 Mon Sep 17 00:00:00 2001
From: avi20091997 <56116189+avi20091997@users.noreply.github.com>
Date: Fri, 11 Oct 2019 15:53:14 +0530
Subject: [PATCH] prime

---
 Prime.cpp | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 Prime.cpp

diff --git a/Prime.cpp b/Prime.cpp
new file mode 100644
index 0000000..e72ce25
--- /dev/null
+++ b/Prime.cpp
@@ -0,0 +1,83 @@
+
+/*https://www.spoj.com/problems/PRIME1/  */
+#include <bits/stdc++.h>
+#define ll long long 
+using namespace std;
+ll sieve[10000001],k;
+//ll mrk[10000001];
+void prime(ll n)
+{
+    ll i,j;
+    k=0;
+    ll mark[n];
+    for(i=0;i<=n;i++)
+    {
+        mark[i]=1;
+    }
+    for(i=2;i<=n;i++)
+    {
+        if(mark[i])
+        {
+            sieve[k]=i;
+            for(j=i;j<=n;j+=i)
+            {
+                mark[j]=0;
+            }
+            k++;
+        }
+    }
+    /*for(i=0;i<sieve.size();i++)
+    {
+        cout<<sieve[i]<<" ";
+    }*/
+}
+void segment(ll l,ll r)
+{
+    ll i,j,lower,n;;
+    n=r-l+1;
+    ll mrk[n];
+    for(i=0;i<n;i++)
+    {
+        mrk[i]=1;
+    }
+    //cout<<k<<" ";
+    for(i=0;i<k;i++)
+    {
+        //cout<<sieve[i]<<" ";
+        lower=(floor(l/sieve[i]))*sieve[i];
+        if(lower<l)
+        {
+            lower+=sieve[i];
+        }
+        if(lower==sieve[i])
+        {
+            lower+=sieve[i];
+        }
+        //cout<<lower<<" ";
+        for(j=lower;j<=r;j+=sieve[i])
+        {
+            mrk[j-l]=0;
+        }
+    }
+    ll count=0;
+    for(i=l;i<=r;i++)
+    {
+        if(mrk[i-l] && i!=1)
+        {
+            cout<<i<<endl;
+        }
+    }
+    cout<<endl;
+}
+int main()
+{
+    ll t,i,j,n,l,r;
+    cin>>t;
+    while(t--)
+    {
+        cin>>l>>r;
+        n=floor(sqrt(r))+1;
+        prime(n);
+        segment(l,r);
+    }
+} 
\ No newline at end of file