solve 14

1 files changed, 65 insertions, 0 deletions

diff --git a/0014/main.pas b/0014/main.pas
new file mode 100644
index 0000000..a79200f
--- /dev/null
+++ b/0014/main.pas
@@ -0,0 +1,65 @@
+program main;
+
+const N = 1000000;
+
+var
+    res: array[1..N] of longint;
+
+function getlen(x: int64): longint;
+var
+    r: longint;
+    sp: longint;
+    argstk: array[1..1000] of int64;
+begin
+    sp := 0;
+    while (x > N) or (res[x] = -1) do
+    begin
+        sp := sp + 1;
+        argstk[sp] := x;
+        if x mod 2 = 1 then
+            x := x * 3 + 1
+        else
+            x := x div 2;
+    end;
+    r := res[x];
+    while sp > 0 do
+    begin
+        if argstk[sp] <= N then
+            res[argstk[sp]] := r + 1;
+        r := r + 1;
+        sp := sp  - 1;
+    end;
+    getlen := r;
+end;
+
+var
+    len: longint;
+    i: longint;
+    maxres: longint;
+    maxlen: longint;
+
+begin
+    len := 0;
+    maxres := 0;
+    maxlen := 1;
+    i := 1;
+    while i <= N do
+    begin
+        res[i] := -1;
+        i := i + 1;
+    end;
+    res[1] := 1;
+
+    i := 1;
+    while i <= N do
+    begin
+        len := getlen(i);
+        if len > maxlen then
+        begin
+            maxres := i;
+            maxlen := len;
+        end;
+        i := i + 1;
+    end;
+    writeln(maxres);
+end.