Grid | Editorial by aksingh007

The problem is a straight forward application of Dijkstra algorithm. We will simply run the dijkstra algorithm once from the given starting/source vertex and store
the result.Hence, further queries could be answered in O(1) time.
NOTE: Use fast I/O.

```
import java.util.*;
import java.io.*;
class TestClass {
    static long solve(long[] factor,long[] arr,int n){
        long cost=0L;long mod=1000000007L;
        for(int i=n-1;i>=0;i--){
            long curcost=((arr[i]%mod)*(factor[n-i-1]%mod)%mod);
            cost=(cost%mod+curcost%mod)%mod;
        }
        return cost%mod;
    }
    
    public static void main(String args[] ) throws Exception {
        long mod=1000000007L;
        Reader sc = new Reader();
        int t=sc.nextInt();
        long factor[]=new long[100001];
        factor[0]=1L;
        factor[1]=2L;
        for(int i=2;i<100001;i++)
            factor[i]=(((i+1)%mod)*(factor[i-1]%mod))%mod;
        //System.out.println(Arrays.asList(factor));
        while(t-->0){
            int n=sc.nextInt();
            long arr[]=new long[n];
            for(int i=0;i<n;arr[i++]=sc.nextLong());
            Arrays.sort(arr);
            System.out.println(solve(factor,arr,n));
        }
    }
    static class Reader{
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;
 
        public Reader(){
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }
 
        public Reader(String file_name) throws IOException{
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }
 
        public String readLine() throws IOException{
            byte[] buf = new byte[1364]; // line length
            int cnt = 0, c;
            while((c=read())!=-1){
                if(c=='\n')
                    break;
                buf[cnt++]=(byte)c;
            }
            return new String(buf,0,cnt);
        }
 
        public int nextInt() throws IOException{
            int ret=0;
            byte c=read();
            while(c<=' ')
                c=read();
            boolean neg=(c=='-');
            if(neg)
                c=read();
            do{
                ret=ret*10+c-'0';
            }while((c=read())>='0' && c<='9');
            if(neg)
                return -ret;
            return ret;
        }
 
        public long nextLong() throws IOException{
            long ret=0;
            byte c=read();
            while(c<=' ')
                c=read();
            boolean neg=(c=='-');
            if(neg)
                c=read();
            do{
                ret=ret*10+c-'0';
            }
            while((c=read())>='0' && c<='9');
            if(neg)
                return -ret;
            return ret;
        }
 
        public double nextDouble() throws IOException{
            double ret=0,div = 1;
            byte c=read();
            while(c<=' ')
                c=read();
            boolean neg =(c=='-');
            if(neg)
                c=read();
            do{
                ret=ret*10+c-'0';
            }
            while((c=read())>='0' && c<='9');
			if(c=='.'){
                while ((c = read()) >= '0' && c <= '9'){
                    ret+=(c-'0')/(div*=10);
                }
            }
            if(neg)
                return -ret;
            return ret;
        }
 
        private void fillBuffer() throws IOException{
            bytesRead = din.read(buffer,bufferPointer=0,BUFFER_SIZE);
            if (bytesRead==-1)
                buffer[0]=-1;
        }
 
        private byte read() throws IOException{
            if (bufferPointer==bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        }
		public void close() throws IOException{
            if (din==null)
                return;
            din.close();
        }
    }
}
```

Grid | Editorial by aksingh007

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