diff --git a/POJ/2823.cpp b/POJ/2823.cpp
new file mode 100644
index 0000000..70788a3
--- /dev/null
+++ b/POJ/2823.cpp
@@ -0,0 +1,81 @@
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <vector>
+using namespace std;
+#define MAXN 1000100
+int bus[MAXN];
+
+int aval[MAXN];
+int apos[MAXN];
+int abegin,aend;
+
+int bval[MAXN];
+int bpos[MAXN];
+int bbegin,bend;
+
+int aans[MAXN];
+int bans[MAXN];
+int cnt;
+
+int main()
+{
+    int N,K;
+    scanf("%d %d",&N,&K);
+    abegin=0;
+    aend=0;
+    bbegin=0;
+    bend=0;
+    cnt=0;
+    /*
+        8 3
+        1 3 -1 -3 5 3 6 7
+    */
+    for(int i=0;i<K;i++)
+    {
+        int t;
+        scanf("%d",&t);
+
+        while(abegin<aend&&aval[aend-1]<=t) aend--;
+        aval[aend]=t;
+        apos[aend++]=i;
+
+        while(bbegin<bend&&bval[bend-1]>=t) bend--;
+        bval[bend]=t;
+        bpos[bend++]=i;
+    }
+    aans[cnt]=aval[abegin];
+    bans[cnt++]=bval[bbegin];
+    for(int i=K;i<N;i++)
+    {
+        int t;
+        scanf("%d",&t);
+
+        while(abegin<aend&&i-apos[abegin]>=K) abegin++;
+        while(abegin<aend&&aval[aend-1]<=t) aend--;
+        aval[aend]=t;
+        apos[aend++]=i;
+
+        while(bbegin<bend&&i-bpos[bbegin]>=K) bbegin++;
+        while(bbegin<bend&&bval[bend-1]>=t) bend--;
+        bval[bend]=t;
+        bpos[bend++]=i;
+
+        aans[cnt]=aval[abegin];
+        bans[cnt++]=bval[bbegin];
+    }
+
+    for(int i=0;i<cnt-1;i++)
+    {
+        printf("%d ",bans[i]);
+    }
+    printf("%d\n",bans[cnt-1]);
+
+    for(int i=0;i<cnt-1;i++)
+    {
+        printf("%d ",aans[i]);
+    }
+    printf("%d\n",aans[cnt-1]);
+
+    return 0;
+}