ui:inputSelect - Aura iteration

Question

<aura:attribute name="lcs" type="Learning_Community__c[]"/> 
<aura:attribute name="lcid" type="String"/>
 <ui:inputSelect aura:id="lc"  change="{!c.onChangeLC}" class="slds-input"
                 labelClass="slds-form-element__label" required="true">            
                        <ui:inputSelectOption text="Select Learning Community..."/>
                        <aura:iteration items="{!v.lcs}" var="lc">
                            <ui:inputSelectOption text="{!lc.Id}" label="{!lc.Name}" />
                       </aura:iteration>
             </ui:inputSelect>

Table:

 <td data-label="Learning Community" title="Learning Community">
                            <ui:inputSelect aura:id="sp" class="slds-input"
                             labelClass="slds-form-element__label" value="{!v.lcid}" required="true" >
                                <ui:inputSelectOption text="--None--" label="--None--"/>
                                    <aura:iteration items="{!v.lcs}" var="lc">
                                        <ui:inputSelectOption text="{!lc.Id}" label="{!lc.Name}" />
                                   </aura:iteration>
                            </ui:inputSelect>                            
                        </td>

Controller:

onChangeLC : function(component,event,helper){
        var selectedLC = component.find("lc").get("v.value");        
        component.set("v.lcid",selectedLC);        
        console.log(selectedLC);
    }

Screenshot:

Problem:

When I change (mass update) the Learning Community (RED) value, it will apply to all the rows in the table, this is working as expected. However, if I change the Learning Community picklist value on individual row level, then it is changing all the rows again which is wrong, expected is to update only to the specific row.

Am I missing anything here?

UPDATE: I have update as per the suggestion

<aura:attribute name="lcid" type="List"/>
<td data-label="Learning Community" title="Learning Community">
                            <aura:iteration items="{!v.lcid}" var="ln">                           
                                <ui:inputSelect aura:id="sp" class="slds-input"
                                 labelClass="slds-form-element__label" value="{!ln.value}" required="true" >
                                    <ui:inputSelectOption text="--None--" label="--None--"/>
                                        <aura:iteration items="{!v.lcs}" var="lc">
                                            <ui:inputSelectOption text="{!lc.Id}" label="{!lc.Name}" />
                                       </aura:iteration>
                                </ui:inputSelect> 
                            </aura:iteration>
                        </td>

Controller:

onChangeLC : function(component,event,helper){
        var selectedLC = component.find("lc").get("v.value");  
        var lcs = [];
            for (var i = 0; i < 20; i++) { 
              lcs.push({
                value: selectedLC
              });
            }
        component.set("v.lcid",lcs);        
        //console.log(selectedLC);
    }

Answer 1

when ever you change a value in redin area that is reflecting in green area because every picklist is connected by there value v.lcid

<ui:inputSelect aura:id="sp" class="slds-input" labelClass="slds-form-element__label" value="{!v.lcid}" required="true" >

thats why whenever you change any input select value in green area all the elements are getting populated by same value because each has value ="{1v.lcid}"

Now to make your code work you should change

<aura:attribute name="lcid" type="String"/>

to

<aura:attribute name="lcid" type="List"/>

and onchangeLc update your code to change value of each element of list

UPDATE

for speed issue can you change your code in controller as it might help

onChangeLC : function(component,event,helper){
        var selectedLC = component.find("lc").get("v.value");  
        var lcs = [];
        var obj ={value: selectedLC}
            for (var i = 0; i < 20; i++) { 
              lcs.push(obj);
            }
        component.set("v.lcid",lcs);        
        //console.log(selectedLC);
    }