From http://www.cnblogs.com/d-e-v-i-l/p/5436931.html

SDUSTOJ/1801.cpp

@@ -0,0 +1,62 @@
+/* ***********************************************
+Author        :devil
+Created Time  :2016/4/26 22:18:57
+************************************************ */
+#include <cstdio>
+#include <cstring>
+#include <iostream>
+#include <algorithm>
+#include <vector>
+#include <queue>
+#include <set>
+#include <map>
+#include <string>
+#include <cmath>
+#include <stdlib.h>
+using namespace std;
+typedef long long LL;
+const int N=110;
+const int mod=1e9+9;
+LL dp[N][N],dp2[N][N];
+int a[N],b[N];
+int main()
+{
+    //freopen("in.txt","r",stdin);
+    int t,n,m;
+    scanf("%d",&t);
+    while(t--)
+    {
+        scanf("%d%d",&n,&m);
+        for(int i=1; i<=n; i++)
+            scanf("%d",&a[i]);
+        memset(dp,0,sizeof(dp));
+        memset(dp2,0,sizeof(dp2));
+        memset(b,-1,sizeof(b));
+        b[a[1]]=dp[a[1]][1]=1;
+        for(int i=2;i<=n;i++)
+        {
+            dp[a[i]][1]=1;
+            int mi=min(i,m);
+            for(int k=2;k<=mi;k++)
+            {
+                for(int j=1;j<a[i];j++)
+                {
+                    dp[a[i]][k]+=dp[j][k-1];
+                    if(dp[a[i]][k]>=mod) dp[a[i]][k]-=mod;
+                }
+                if(b[a[i]]!=-1)
+                {
+                    dp[a[i]][k]-=dp2[a[i]][k];
+                    if(dp[a[i]][k]<0) dp[a[i]][k]+=mod;
+                }
+                dp2[a[i]][k]=dp[a[i]][k];
+            }
+            b[a[i]]=i;
+        }
+        LL ans=0;
+        for(int i=1;i<=n;i++)
+            ans=(ans+dp[i][m])%mod;
+        printf("%lld\n",ans);
+    }
+    return 0;
+}