From 2f674dc80f0382f1c3178f435714960734dc9d3c Mon Sep 17 00:00:00 2001
From: Nguyễn Gia Phong <mcsinyx@disroot.org>
Date: Sat, 6 Jun 2020 21:33:13 +0700
Subject: Reorganize stuff from secondary school

---
 2ndary/12/TP-HN-2009/R2/BAI1.PAS | 90 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 2ndary/12/TP-HN-2009/R2/BAI1.PAS

(limited to '2ndary/12/TP-HN-2009/R2/BAI1.PAS')

diff --git a/2ndary/12/TP-HN-2009/R2/BAI1.PAS b/2ndary/12/TP-HN-2009/R2/BAI1.PAS
new file mode 100644
index 0000000..b28ae0b
--- /dev/null
+++ b/2ndary/12/TP-HN-2009/R2/BAI1.PAS
@@ -0,0 +1,90 @@
+uses math;
+
+var
+  f : text;
+  n : longint;
+  lena, i : integer;
+  a : array[1..512] of longint;
+
+procedure insort(x : longint);
+  var i, j : integer;
+  begin
+    inc(lena);
+    a[lena] := x - 1;
+    for i := 1 to lena do
+      if a[i] < x then begin
+        for j := lena downto i + 1 do
+          a[j] := a[j - 1];
+        a[i] := x;
+        exit
+      end
+  end;
+
+function notin(x : longint) : boolean;
+  var l, h, m : integer;
+  begin
+    l := 1;
+    h := lena;
+    repeat
+      m := (l + h) div 2;
+      if a[m] = x then exit(false);
+      if a[m] < x then h := m - 1
+      else l := m + 1
+    until l > h;
+    notin := true
+  end;
+
+procedure mklist(n0 : longint);
+  var
+    i, j : byte;
+    n10, m0 : longint;
+  begin
+    if n0 <> 0 then begin
+      insort(n0);
+      for i := 0 to trunc(log10(n0)) do
+        begin
+          n10 := 1;
+          for j := 1 to i do n10 := n10 * 10;
+          m0 := n0 div (n10 * 10) + n0 mod n10;
+          if notin(m0) then mklist(m0)
+        end
+    end
+  end;
+
+function prime(m : longint) : boolean;
+  var p, q : integer;
+  begin
+    if m < 2 then exit(false);
+    if m = 2 then exit(true);
+    if m = 3 then exit(true);
+    if m mod 2 = 0 then exit(false);
+    if m mod 3 = 0 then exit(false);
+    p := 5;
+    q := 2;
+    while p * p <= m do
+      begin
+        if m mod p = 0 then exit(false);
+        p := p + q;
+        q := 6 - q
+      end;
+    prime := true
+  end;
+
+begin
+  assign(f, 'BAI1.INP');
+  reset(f);
+  read(f, n);
+  close(f);
+  lena := 0;
+  mklist(n);
+  assign(f, 'BAI1.OUT');
+  rewrite(f);
+  for i := 1 to lena do
+    if prime(a[i]) then begin
+      writeln(f, a[i]);
+      close(f);
+      exit
+    end;
+  writeln(f, -1);
+  close(f)
+end.
-- 
cgit 1.4.1