What would be time complexity of below problem?

class Solution $\{$

public:

bool isValid$($vector& weights, int days $,$int mid $)\{$

int d $=1,$ sum $=0$ ;

for $($ int i $=0$ ; i $<$ weights.size$()$ ; i$++)\{$

if $($ sum $+$ weights$[$i$]<=$ mid $)\{$

sum $+=$ weights$[$i$]$ ;

$\}$

else $\{$

d$++$;

sum $=$ weights$[$i$]$;

if$($ d $>$ days $||$ weights$[$i$]>$ mid $)$ return false ;

$\}$

$\}$

return true ;

$\}$

int shipWithinDays$($vector& weights, int days$)\{$

int start $=0,$ end $=0,$ mid $,$ answer $=0$ ;

for $($ int i $=0$ ; i $<$ weights.size$()$ ; i$++)\{$

end $+=$ weights$[$i$]$ ;

$\}$

while $($ start $<=$ end $)\{$

mid $=$ start $+($ end $-$ start $)/2$ ;

if$($isValid$($ weights $,$ days $,$mid $))\{$

answer $=$ mid ;

end $=$ mid $-1$ ;

$\}$

else $\{$

start $=$ mid $+1$ ;

$\}$

$\}$

return answer ;

$\}$

$\}$;