Problem:
Score : 700 points

Problem Statement

There are N stones arranged in a row. The i-th stone from the left is painted in the color C_i.

Snuke will perform the following operation zero or more times:

Choose two stones painted in the same color. Repaint all the stones between them, with the color of the chosen stones.

Find the number of possible final sequences of colors of the stones, modulo 10^9+7.

Constraints

1 \leq N \leq 2\times 10^5

1 \leq C_i \leq 2\times 10^5(1\leq i\leq N)

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
C_1
:
C_N

Output

Print the number of possible final sequences of colors of the stones, modulo 10^9+7.

Sample Input 1

5
1
2
1
2
2

Sample Output 1

3

We can make three sequences of colors of stones, as follows:

(1,2,1,2,2), by doing nothing.

(1,1,1,2,2), by choosing the first and third stones to perform the operation.

(1,2,2,2,2), by choosing the second and fourth stones to perform the operation.

Sample Input 2

6
4
2
5
4
2
4

Sample Output 2

5

Sample Input 3

7
1
3
1
2
3
3
2

Sample Output 3

5

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
import java.io.*;

import static java.lang.Math.*;
import static java.util.Arrays.*;
import static java.util.Collections.*;
 
public class Main{
    static final long mod=1000000007;
//    static int dx[]={-1,0,1,0};
//    static int dy[]={0,-1,0,1};

    public  static void main(String[] args)   throws Exception, IOException{        
        Reader sc = new Reader(System.in);
        //110110011
        PrintWriter out=new PrintWriter(System.out);
        // int n=sc.nextInt();
        int n=sc.nextInt();
        int c=2*100000+1;
        
        long e[]=new long[c];
        int pre=-1;
        long ans=1;
        for (int i = 0; i < n; i++) {
			int x=sc.nextInt()-1;
			if(pre==x) {
				continue;
			}
			e[x]=e[x]+ans;
			e[x]%=mod;
			ans=e[x];
			pre=x;
//			db(pre,x,ans);
		}


        out.println(ans);
        out.flush();
    }



    static boolean validpos(int x,int y,int r, int c){
        return x<r && 0<=x && y<c && 0<=y;
    }

    static void db(Object... os){
        System.err.println(Arrays.deepToString(os));
    }  
}

//class P {
//    int id, d;
//    P(int  id, int d) {
//        this.id=id;
//        this.d=d;
//    }
//}

class P implements Comparable<P>{
    int id,T;
    P(int id, int T) {
        this.id=id;
        this.T=T;
    }
    public int compareTo(P p){
        return id-p.id; //des
    }
}

class Reader
{ 
    private BufferedReader x;
    private StringTokenizer st;
    
    public Reader(InputStream in)
    {
        x = new BufferedReader(new InputStreamReader(in));
        st = null;
    }
    public String nextString() throws IOException
    {
        while( st==null || !st.hasMoreTokens() )
            st = new StringTokenizer(x.readLine());
        return st.nextToken();
    }
    public int nextInt() throws IOException
    {
        return Integer.parseInt(nextString());
    }
    public int[] nextIntArray(int size) throws IOException{
    	int r[] = new int[size];
    	for (int i = 0; i < size; i++) {
			r[i] = this.nextInt(); 
		}
    	return r;
    }
    public long[] nextLongArray(int size) throws IOException{
    	long r[] = new long[size];
    	for (int i = 0; i < size; i++) {
			r[i] = this.nextLong(); 
		}
    	return r;
    }
    public long nextLong() throws IOException
    {
        return Long.parseLong(nextString());
    }
    public double nextDouble() throws IOException
    {
        return Double.parseDouble(nextString());
    }
}