# Lisa Soros
# 7/18/2012
# Solution to BHCSI Contest Problem: Cloudnet

def flip(switch):
    if switch=="1":
        return "0"
    else:
        return "1"

def main():

    infile = open('cloudnet.in', 'r')
    num_cases = int(infile.readline())

    # Go through each case.
    for case in range(num_cases):
        num_switches = int(infile.readline())
        panel = infile.readline().split()

        indexlist = list(range(num_switches))
        indexlist.reverse()

        # Go through the list in reverse order.
        for mindex in indexlist:

            # Calculate my left and right indexes.
            lindex = mindex-1
            rindex = mindex+1
        
            if mindex==0:
                lindex = num_switches-1
            elif mindex==num_switches-1:
                rindex = 0

            # Rule B
            if panel[mindex]==panel[lindex] and panel[mindex]==panel[rindex]:
                panel[mindex] = flip(panel[mindex])

            # Rule D
            elif panel[mindex]==panel[lindex]:
                panel[lindex] = flip(panel[lindex])

            # Rule C
            elif panel[mindex]==panel[rindex]:
                panel[mindex] = flip(panel[mindex])

            # Rule A
            else:
                panel[rindex] = flip(panel[rindex]);
                panel[mindex] = flip(panel[mindex]);
                panel[lindex] = flip(panel[lindex]);

        # Print the end state.
        for i in range(num_switches):
            print(panel[i], end='')
        print()

    infile.close()

main()