c++ - To check whether an integer is a palindrome in O(1) space(Wrong answer) -

-

i tried solving question reversing number ,using bitwise operations:- example if number's binary representation 00000110 ,what code is, send 0000011 code , left shift reverse_num 5 times 01100000, reverse of original,after program "&" of number original number.if answer 1 ,then number said palindrome else false returned.is there flaw in logic? if there ,i think it's in & part.

class solution { public:     bool ispalindrome(int x) {         if(x<0)             return false;         int num=x;         int reverse_num=x;         int count=sizeof(x);         num >>= 1;         while(num)             {                 reverse_num <<= 1;                       reverse_num |= num & 1;                 num >>= 1;                 count--;             }         reverse_num <<= count;          if(!(reverse_num&x))             return true;         else return false;     } };

i still want know wrong previous code . sorry asking such silly question .i noob in programming. original question here:https://oj.leetcode.com/problems/palindrome-number/

although able around question doing this:

class solution { public:     bool ispalindrome(int x) {         long long y=0;         long long t=x;         long long p;         p=x;         while(t){             y=y*10+t%10;             t=t/10;         }         if(p==y && p>=0)             return true;         else return false;      }  };

for final if statement, && logical and. in c/c++ (and many other languages), logical test on integer return true unless value 0.

so function return true if either x or reverse_num 0


Comments

Post a Comment

Popular posts from this blog

c++ - OpenCV Error: Assertion failed <scn == 3 ::scn == 4> in unknown function, -

-
i read alot other solution still confused should mine... #include <opencv2/objdetect/objdetect.hpp> #include <opencv2/highgui/highgui.hpp> #include <opencv2/imgproc/imgproc.hpp> #include <iostream> #include <stdio.h> using namespace std; using namespace cv; int main(int argc, const char** argv) { //create cascade classifier object used face detection cascadeclassifier face_cascade; //use haarcascade_frontalface_alt.xml library face_cascade.load("haarcascade_frontalface_alt.xml"); //setup video capture device , link first capture device videocapture capturedevice; capturedevice.open(0); //setup image files used in capture process mat captureframe; mat grayscaleframe; //create window present results namedwindow("outputcapture", 1); //create loop capture , find faces while (true) { //capture new image frame capturedevice >> captureframe; ...
Read more

php - render data via PDO::FETCH_FUNC vs loop -

-
i've been using 2 methods render data. the first one: function name($id,$name){ return '<div id="'.$id.'">'.$name.'</div>'; } echo implode($pdo->query("select id,name user")->fetchall(pdo::fetch_func,'name')); the second one: $users = $pdo->query("select id,name user")->fetchall(pdo::fetch_obj); foreach($users $user){ echo name($user->id,$user->name); } i don't understand how pdo::fetch_func works. tried figure out. however, not well-documented. could please explain fetch mode? , also, 1 performs better? thank you. both methods wrong , have learn how use templates , how separate business logic presentation logic. $users = $pdo->query("select id,name user")->fetchall(pdo::fetch_obj); tpl::assign('users', $users); is code business logic part. then in template <?php foreach $users $row): ?> <div id="<?=$...
Read more

The canvas has been tainted by cross-origin data in chrome only -

-
uncaught securityerror: failed execute 'getimagedata' on 'canvasrenderingcontext2d': canvas has been tainted cross-origin data i getting above error in chrome. code(following) works fine in mozilla. have not corss domain issue. why above error in chrome? var wheel_canvas, wheel_context, can_w, can_h, wheel_grd; var large_radius = 160; var small_radius = 120; var wheel_canvas = document.getelementbyid('wheel_canvas'); var wheel_context = wheel_canvas.getcontext('2d'); var can_w = $(wheel_canvas).width(); var can_h = $(wheel_canvas).height(); var centerx = can_w / 2, centery = can_h / 2; var wheel_grd = null; test('#ff0000'); function test(hex) { $('#clrpicker').css({'left': 210, 'top': 210 }); inverted = hexbw(hex); $('#color_val_show').val(hex); current_color_hex_val_selected = hex; $('#color_val_show').css({'color':inverted,'background':hex}); fillgradient...
Read more