[miokie]

pawn Код:

new Team1;
new Team2;
new PlayerTeam[playerid];

When a player tries to join team 1:

pawn Код:

if(Team1 < Team 2) //Checks if Team 1 has less players than team 2
{
Team1 += 1; //adds a player to the team
PlayerTeam[playerid] = 1;
return 1; //spawns the player
}
else
{
SendClientMessage(playerid,COLOR,"...");//Message telling the player the team wouldnt be balanced if they joined it.
return 0; // Makes it so the player dosen't spawn.
}

Do the same for team 2.

On Disconnect:

pawn Код:

if(PlayerTeam[playerid] == 1)
{
Team1 -= 1;
}
else
{
Team2 -= 1;
}

UNTESTED. Should work, I think you get the point