Questions tagged [binary-search]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
4 votes
1 answer
26 views

What if binary search's split was not in the middle, but in a way the left side is twice as long as the right side?

How would the time complexity change if the binary search's split was not in the middle ((left + right)/2), but rather in such a way that the left side is twice as long as the right side? So we check ...
Mia W's user avatar
  • 41
0 votes
1 answer
35 views

when to search in binary search right, when left?

in the binary search algorithm: If no items Return false If middle item is 50 Return true Else if 50 < middle item Search left half Else if 50 > middle item Search right half like can we do the ...
sumer fattoum's user avatar
0 votes
1 answer
151 views

Purpose of sizeof(book)/sizeof(string) in lectures' binary sort?

string book[] = { "Chen", "Kernighan", "Leitner", "Lewis", "Malan", "Muller", "Seltzer", "Shieber", "Smith" } int main(...
Davis's user avatar
  • 144
0 votes
1 answer
25 views

Code won't progress unless user inputs a number

I was writing a binary search function before finishing lecture 3 because I wanted to do some practice on my own. I was using scanf, which I had looked up, as I wanted to learn how to code without the ...
Mark Cangila's user avatar
0 votes
1 answer
38 views

find problem with my code - CPU overload

I cannot figure out what is wrong with my code. /** * Returns true if value is in array of n values, else false. */ bool search(int value, int values[], int n) { // ensures that the n is non ...
koko loko's user avatar
0 votes
1 answer
118 views

pset3 find less comfortable if else expression result unused

I do not understand why I get an errors: error: expected ';' after expression else (value > values[l]) and helpers.c:40:21: error: expression result unused [-Werror,-Wunused-value] ...
koko loko's user avatar
0 votes
1 answer
57 views

CS 50 - pset3 find helpers: Why do binary search and selection short not work?

the command line yells at me but I cannot find out why. Any ideas what could be wrong? Here is my code: /** * helpers.c * * Helper functions for Problem Set 3. */ include include "helpers.h" /...
AlexL's user avatar
  • 5
0 votes
2 answers
246 views

PSET3 find having trouble. Can someone help?

For some reason bubble sort is not working. Can someone help. binary search bool search (int target, int array[],int length) { int end = length-1; int start = 0; while (array[start] < ...
user20243's user avatar
0 votes
1 answer
72 views

pset3: sort and search work in separate files, but my helpers.c doesn't work

I dealt with sorting in a separate file first, and then I dealt with searching in another file. They seem to work okay or at least worked for the numbers I feed in, but when I put them in helpers and ...
Chris's user avatar
  • 19
0 votes
0 answers
26 views

For pset3 binary search will this code work?

Here is the code . bool binary_search (int target, int array[],int length) { int end = length-1; int start = 0; while ( array[end_num]- array[start_num] > 0) { ...
Tom55555's user avatar
0 votes
1 answer
35 views

do I need recurson for binary search?

Also do I need recursion for any of the pset3 solutions? If yes any good sources on recursion. There was a quick example in lecture 3. Will that suffice? Preferably a video. I realize I could just ...
Tom55555's user avatar
0 votes
1 answer
66 views

Find.c - Binary Search probable integer overflow

Here's the gist: https://gist.github.com/Securiteru/a83e4f1a028acd0b1013def793b5dcdc And the output: ... 60697 61151 61190 61275 61460 61608 61618 61746 61750 61822 62111 62178 62183 62311 62448 ...
Securiter's user avatar
0 votes
1 answer
419 views

Pset3, Find, search

In "Find" problem, something seems wrong with my binary search Algorithm, because in check50, helpers.c wouldn't compile, I tried to compile it, then it gave me this weird error: clang -fsanitize=...
Raw's user avatar
  • 9
0 votes
2 answers
65 views

pset 3 binary search help

I am working on pset 3 for cs50 on edx, and I'm having quite a bit of trouble with the binary search problem. My program worked fine when I tested it with a linear search (so I think the problem isn'...
ParzivalBlade's user avatar
0 votes
1 answer
119 views

PSET3 Binary Search Function Infinite Loop

When I try running find.c inputting: ./generate 1000 50 | ./find 127 it should return that the value (127) was found, however when I do it with my code, it seems to create an infinite loop. Also, ...
hpati1117's user avatar
0 votes
2 answers
191 views

Pset3 helpers.c

i'm stuck in binary search. Check50 doesn't pass all the checks and it doesn't find the needle, I feel like the algorithm i have implemented is correct but it doesn't work. I've been stuck in this for ...
Ishark Felician's user avatar
0 votes
2 answers
162 views

Binary Search for helpers.c

so as the title suggests I am having some trouble with my implementation of binary search. So based on the logic shown in the lecture, I think my implementation is fine, indeed it works for the cases ...
Anza Khan's user avatar
1 vote
2 answers
104 views

Binary Search Pset 3 help

As my question is titled, I would appreciate help with my binary search, shown below. Currently, the search will always return false. I am almost certain that my sorting algorithm is correct, as it ...
Jason_V's user avatar
  • 182
0 votes
2 answers
160 views

Segmentation Fault pset3 for Find

I'm getting a segmentation fault error and I can't figure out why. void sort(int values[], int n) { // TODO: implement a sorting algorithm for (int i = 0; i<n; i++) { if ((n!=i+...
Alex Durante's user avatar
0 votes
0 answers
51 views

Result doesn't match expected output

I just finished the helpers.c pset, where you have to implement a counting sort and then a binary search. I havent made it recursive yet but it works in all of my own test cases. I also ran the ./...
Tod Lazarov's user avatar
0 votes
1 answer
76 views

pset3: search (am I in the right track??)

bool search(int value, int values[], int n) //search for middle lists if (value == values [n / 2]) { return 1; } //number greater search left else if ( value > values[n / 2 ]) { search(int ...
RedRabbit's user avatar
0 votes
1 answer
109 views

Pset 3 Recursive Binary Search problems - Always returns true

I have tried almost everything and edited my code a hundred times in search of an answer. It seems that whenever I run the program (find.c) the result always resolves to true. Not sure where the ...
Mo Amer's user avatar
2 votes
2 answers
25k views

Question about binary search. Please help!

https://www.youtube.com/watch?v=5xlIPT1FRcA&t=200s I am struggling to understand how to implement binary search. According to the video, there are 14 numbers in the array. Then he goes on to ...
Thuy's user avatar
  • 25
0 votes
1 answer
678 views

cs50x pset3 find - Need help with the counting sort

can someone please look at my code and tell me where I went wrong with my counting sort algorithm (Or binary search algorithm, if that's where the problem lies...?). Please and thank you. Binary ...
Milad's user avatar
  • 7
0 votes
2 answers
33 views

C: Binary Search searches and finds but incorrect exit code

This code is finding all the numbers correctly. Only problem is it's throwing error of "\ expected an exit code of 1, not 0" when the number is not present. Help would be appreciated. bool search(int ...
Android1's user avatar
0 votes
1 answer
32 views

Advice re: Binary search - various issues

I need advice as to what to change in this code to make it work. I am new at this so I need specifics, please. Please, no opinions on whether it's trash or what mark you would give if grading it. That ...
Android1's user avatar
1 vote
2 answers
38 views

C: Pset 3: Binary Search - 'expected an exit code of 0, not 1' (not finding n)

This is an attempt at binary search. n is the user input (from main script). This code compiles but doesn't find the needle in the haystack. I'm a bit lost and would welcome assistance. bool ...
Android1's user avatar
0 votes
1 answer
59 views

please help me with this binary search

for some reason this binary search code keeps returning true, when providing the haystack from generate.c, even if the "needle" isnt there. when manually inputing the haystack, the code runs perfectly....
David Rosenberg's user avatar
0 votes
1 answer
97 views

Pset 3: Find (more comfortable) - child exited with status 255 & exits with wrong code

I ambitiously decided to try the more comfortable version of this task, although I'm very much "less comfortable" with regard to any computer skills... Before I give up, I'd like to ask you what's ...
randomshiners's user avatar
0 votes
0 answers
218 views

PSET3 \ expected an exit code of 0, not 1 (find.c)

I successfully built my program and went on to check it using check50 only to discover this :) helpers.c exists :) helpers.c compiles :) finds 42 in {42,43,44} :) finds 42 in {41,42,43} :) finds 42 ...
Ubuntu NutCracker's user avatar
0 votes
1 answer
95 views

Pset3 Find - Not sure what is wrong with helpers.c code

I am not sure what is wrong with the code. It seems to work on some of the criteria when using cs50's check50, but does not work on others. There also does not seem to have a pattern about the wrong ...
KayZee's user avatar
  • 3
0 votes
1 answer
39 views

Recursive function problem - return value

I am getting the following error below. It has to do with my binarySearch function. helpers.c:149:1: error: control may reach end of non-void function [-Werror,-Wreturn-type] } ^ However I have a ...
Salamit's user avatar
  • 231
0 votes
1 answer
48 views

Pset3 helpers.c while loop exiting unexpectedly

I am trying to implement a binary search algorithm. However, my while loop isn't working as expected. Having used printf and debug50 with a list of 100 numbers, it seems that the while loop only gets ...
An_antelope's user avatar
0 votes
1 answer
101 views

Binary Search pset3

bool search(int value, int values[], int n) { int found = 0; int notfound = 0; int minindex = 0; int maxindex = n; int midindex = 0; do { midindex = (minindex + maxindex) / 2; if (minindex &...
helprequest's user avatar
0 votes
1 answer
340 views

PSet 3, binary search implementation

I'm struggling with implementation of binary search in PSet 3, and my code can't quite get past check50. Here's my code: bool search(int value, int values[], int n) { // TODO: implement a ...
Athena's user avatar
  • 1
0 votes
1 answer
167 views

helpers.c passes check50 but fails ./generate 1000 50 | ./find 128

check50 gives me all smiles, but when I run the test code ./generate 1000 50 | ./find 127 or 128 they both return "Found needle in haystack". How is that possible? And also, can I be sure my code is ...
Lele's user avatar
  • 67
0 votes
1 answer
50 views

pset3 binary search , shows errors in check50

i don't understand acc. to the algorithm it should work correctly , but it doesn't
Ketan Verma's user avatar
0 votes
1 answer
100 views

pset3 binary search , problems with check50

i have tried a lot but cannot find the meaning of the last two errors of check50 please help
Ketan Verma's user avatar
0 votes
1 answer
32 views

pset3: When testing binary search code, how do I print when needle is found?

I would like to test if my binary search function is working correctly. I have created an array that is passed into a working bubble sort function. Printing the sorted array works just fine, all I ...
Kgotso Koete's user avatar
0 votes
1 answer
81 views

Pset3 recursive binary search function - check50 gives me four :( and I don't know why

I would be really grateful if someone could offer me a hint as to where I'm going wrong with this - I've been stuck for a couple of days now. When I work through the code step by step on paper it ...
J M COOPER's user avatar
0 votes
1 answer
55 views

binary search algorithm

Many sources say that you need to put "int l = n" the element next to last instead of "int l = n - 1"(int f = 0; int l = n - 1; int mid;) in my example. I am not sure why? Moreover it seems my code ...
Michael Lil's user avatar
0 votes
1 answer
49 views

return -1 does not end function execution

This is my code. 65 int BinarySearch(int key, int array[], int min, int max) 66 { 67 int mid; 68 69 if (max < min) 70 { 71 return -1; 72 } 73 else 74 ...
Alexis's user avatar
  • 25
0 votes
1 answer
166 views

How do I set a pointer to access the left half of an array? [PSET 3 - Binary search]

I'm having trouble accessing only the left half of an array, doing the same for the right half works fine for now, at least I'm not getting any errors. I figured accessing the array using pointers ...
kluvin's user avatar
  • 1,223
0 votes
1 answer
178 views

Segmentation fault in find.c

I've been working on find.c for a long time now and I've managed to get to the point where it will return the correct output when the needle is in the haystack, but when it isn't I get a segmentation ...
Danielle R's user avatar
0 votes
2 answers
73 views

find.c compiles but fails check50 - I believe binary search is to blame

Why does my code fail check50? This is the code of my binary search. I know it's buggy, and I spent the last hours reading answers to similar questions, the information I found doesn't quite cut it ...
Iury Sikorsky's user avatar
0 votes
1 answer
104 views

Check50 is claiming that it's recieving an exit code of 0 rather than 1 (different scenario)

I know this question has been answered before (pset 3 "search": expected an exit code of 0, not 1), but I took a look at it, and it seems that the scenario in which the person asked the ...
jayfeather31's user avatar
0 votes
1 answer
305 views

Stuck in loop on Binary Search

I have some problems with my Binary search and would greatly apprecaite help in this. I've debugged it and it seems that my "mid" variable doesn't change. As such, if "value" doesn't equal value[mid] ...
Domoman's user avatar
0 votes
2 answers
67 views

binary search pset 3 pointer to integer error

I am trying my hands on binary search. I get those pointer to integer errors :( Can sonmeone more experience give me a hand ? bool search(int value, int values[], int n) { int first=0; int last=n-1; ...
hmmmbob's user avatar
  • 105
0 votes
1 answer
23 views

Binary search: always false when 2 or 3 numbers entered

My binary search works correctly when you enter 1,4,5,6,7 (etc)... numbers or 'haystacks'. However, when 2 or 3 numbers or 'haystacks' are entered, false is always returned. I have tried everything I ...
Iris Frenzy's user avatar
0 votes
1 answer
104 views

What's wrong with my recursive binary search function? [duplicate]

I've spent hours on this, have tried multiple configurations based on code I can find online, but am getting no where. Any input would be appreciated. I'm trying to make a recursive, binary search ...
user avatar