194. Leetcode solution in bash

# NF represents the number of fields in the current record, that is, how many columns are there
# NR indicates the number of records that have been read, which is the line number
awk '{
    for (i = 1; i <= NF; ++i) {
        if (NR == 1) s[i] = $i;
        else s[i] = s[i] " " $i;
    }
} END {
    for (i = 1; s[i] != ""; ++i) {
        print s[i];
    }
}' file.txt