Throw Rigibody2D cannon to a 2D target (with gravity), reach in time, how to calculate Addforce ? Please & Thx

This is the simulate picture:

And here is my testing Script.. may have so many logic errors..

 void Fire_CannonInSeconds(GameObject oBullet, float fTotalTime) {
     if (oBullet==null)
         return;
     // Total X range
     float fXRange = Mathf.Abs( trTarget.localPosition.x - oBullet.transform.localPosition.x );
     // 
     float forceRight = oBullet.rigidbody2D.mass * (fXRange / fTotalTime);

     // SET: the reach Top point time = Total * 2 / 3..
     float fToTopTime = fTotalTime * 2f / 3f;
     // SET: Top Point
     float fTop = Mathf.Max( trTarget.localPosition.y, oBullet.transform.localPosition.y ) + 0.2f;
     // calculate Bullet to top point movement range
     float fMoveY = fTop - oBullet.transform.localPosition.y;
     // here ... i don't know how to ... so...
     float fTot = Physics2D.gravity.magnitude * oBullet.rigidbody2D.mass * (fMoveY / (fToTopTime / Time.fixedDeltaTime));
     // seems not work here..
     float forceUp = Physics2D.gravity.magnitude + fTot ;

     oBullet.SetActive(true);
     oBullet.rigidbody2D.AddForce (Vector3.up * forceUp);           
     oBullet.rigidbody2D.AddForce (Vector3.right * forceRight);   
 }

Thank you very much Q_Q