//Globals
new requestedTeam[MAX_PLAYERS];

//OnPlayerRequestClass
requestedTeam[playerid] = classid;

//OnPlayerRequestSpawn
new teamTerroristsPlayers, teamSwatPlayers;
for(new otherplayerid = 0, playerCount = GetPlayerPoolSize(); otherplayerid <= playerCount; otherplayerid++) {
    if(gTeam[otherplayerid] == TERRORISTS) {
        teamTerroristsPlayers++;
    } else {
        teamSwatPlayers++;
    }
}
//If there are less terrorists than swat players and the player chose the swat class
//OR if there are less swat than terrorists players and the player chose the terrorists class
if((teamTerroristsPlayers < teamSwatPlayers && requestedTeam[playerid] == USE_SWAT_CLASS_HERE)
|| (teamSwatPlayers < teamTerroristsPlayers && requestedTeam[playerid] == USE_TERRORISTS_CLASS_HERE)) {
    return 0; //Don't let the player spawn
} 
//If there are less terrorists than swat players and the player chose the terrorists class
//OR if there are less swat than terrorists players and the player chose the swat class
//OR if the amount of terrorists players is equal to the amount of swat players, regardless of the chosen class
else {
    if(requestedTeam[playerid] == USE_TERRORISTS_CLASS_HERE) {
        gTeam[playerid] = TERRORISTS;
    } else {
        gTeam[playerid] = SWAT;
    }
    return 1; //Let the player spawn
}

//OnPlayerRequestClass
new teamTerroristsPlayers, teamSwatPlayers;
for(new otherplayerid = 0, playerCount = GetPlayerPoolSize(); otherplayerid <= playerCount; otherplayerid++) {
    if(gTeam[otherplayerid] == TERRORISTS) {
        teamTerroristsPlayers++;
    } else {
        teamSwatPlayers++;
    }
}
if((teamTerroristsPlayers < teamSwatPlayers && classid == USE_SWAT_CLASS_HERE)
|| (teamSwatPlayers < teamTerroristsPlayers && classid == USE_TERRORISTS_CLASS_HERE)) {
    return 0;
} else {
    if(classid == USE_TERRORISTS_CLASS_HERE) {
        gTeam[playerid] = TERRORISTS;
    } else {
        gTeam[playerid] = SWAT;
    }
    return 1;
}