What is the time complexity for each class? O $(....)?$ Please explain why it's like that.

$1.$ Problem $1-$ while loop with nested for loop

public static void foo$1($int$[]$ arr$)\{$

$$ int j $=1$;

$$ int n $=$ arr.length;

$$ while $($j $<$ n$)\{$

$$ for $($int k $=0$; k $<$ arr.length; k$++)\{$

$$ System.out.print$("*")$;

$\}$

$$ System.out.println$("$$ $")$;

$$ j $=$ j $*2$;

$\}$

$$ System.out.println$()$;

$\}$

$2.$ Problem $2-$ a for loop

$$public static void foo$2($int$[]$ arr$)\{$

$$ for $($int i $=1$; i $<$ arr.length; i $*=2)\{$

$$ System.out.print$("$# $")$;

$\}$

$$ System.out.println$()$;

$\}$

$3.$ two for loops

public static void foo$3($int$[]$ arr$)\{$

$$ for $($int i $=1$; i $<$ arr.length; i $*=2)\{$

$$ System.out.print$("$@ $")$;

$\}$

$$ System.out.println$()$;

$$ for $($int j $=0$; j $<$ arr.length; j$++)\{$

$$ System.out.print$("$& $")$;

$\}$

$$ System.out.println$()$;

$\}$

$4.$ Problem $4-$ a for loop

public static void foo$4($int$[]$ arr$)\{$

$$ for $($int j $=0$; j $<$ arr.length; j$++)\{$

$$ System.out.print$("\%")$;

$\}$

$$ System.out.println$()$;

$\}$

$5.$ Problem $5-$ two nested for loops looking for two numbers that sum up to the target

public static int$[]$ twoSum$($int$[]$ nums, int target$)\{$

$$ for $($int i $=0$; i $<$ nums.length; i$++)\{$

$$ System.out.print$($nums$[$i$]+"$:$\backslash$t $")$;

$$ for $($int j $=$ i $+1$; j $<$ nums.length; j$++)\{$

$$ System.out.print$($nums$[$j$]+",")$;

$$ if $($nums$[$i$]+$ nums$[$j$]==$ target$)\{$

$$ return new int$[]\{$ i$,$ j $\}$;

$\}$

$\}$

$$ System.out.println$()$;

$\}$

$$ return null;

$\}$