bhushanz i have come up with the best logic return((a>b?a:b)>(c>d?c:d)?(a>b?a:b):(c>d?c:d));
sujayh19881 Yup this is elegant!!! But its similar to if statements>I feel there are many more if statements(implicit) than the starightforward if. Anyway its elegant!! :)
kodeerder Ultimate
Apocalipsis It's easy to read but not efficient. An efficient code should be like this: return a>b?(c>d?(c>a?c:a):(d>a?d:a)):(c>d?(c>b?c:b):(d>b?d:b)); but isn't easy to read...
alaniane Efficient code is code that generates the least amount of machine instructions or unrolls loops not what looks efficient in higher level language. Take both samples of code and compile them and then look at the assembly generated. When you write code with a lot of nested ternary operators the compiler cannot perform its optimizations correctly. So,
if (x == y){ ... }else if(y == z){ ... }else if(z > w){ ... }else{ ... }
will optimize better than
(x==y)?...:(y==z)?...:(z > w)?...:...
alaniane To show how compiler view things:
void printMax(int a, int b, int c, int d){ int max = a; if(b > max){ max = b; } if(c > max){ max = c; } if(d > max){ max = d; } printf("%d\n", max); } void printMaxTwo(int a, int b, int c, int d){ printf("%d\n", ((a>= b && a >= c && a >= d)?a:(b > a && b > c && b > d)?b:(c > a && c > b && c > d)?c:d)); } void printMaxThree(int a, int b, int c, int d){ if(a >= b && a >= c && a >= d){ printf("%d\n", a); }else if(b > a && b > c && b > d){ printf("%d\n, b"); }else if(c > a && c > b && c > d){ printf("%d\n", c); }else{ printf("%d\n", d); } }
Here is the assembly generated by the compiler for the first one:
0x401460 push %ebp 0x401461 mov %esp,%ebp 0x401463 sub $0x28,%esp 0x401466 mov 0x8(%ebp),%eax 0x401469 mov %eax,-0xc(%ebp) 0x40146c mov 0xc(%ebp),%eax 0x40146f cmp -0xc(%ebp),%eax 0x401472 jle 0x40147a <printMax+26> 0x401474 mov 0xc(%ebp),%eax 0x401477 mov %eax,-0xc(%ebp) 0x40147a mov 0x10(%ebp),%eax 0x40147d cmp -0xc(%ebp),%eax 0x401480 jle 0x401488 <printMax+40> 0x401482 mov 0x10(%ebp),%eax 0x401485 mov %eax,-0xc(%ebp) 0x401488 mov 0x14(%ebp),%eax 0x40148b cmp -0xc(%ebp),%eax 0x40148e jle 0x401496 <printMax+54> 0x401490 mov 0x14(%ebp),%eax 0x401493 mov %eax,-0xc(%ebp) 0x401496 mov -0xc(%ebp),%eax 0x401499 mov %eax,0x4(%esp) 0x40149d movl $0x405064,(%esp) 0x4014a4 call 0x403bf0 <printf> 0x4014a9 nop 0x4014aa leave 0x4014ab ret
For the second one:
0x4014ac push %ebp 0x4014ad mov %esp,%ebp 0x4014af sub $0x18,%esp 0x4014b2 mov 0x8(%ebp),%eax 0x4014b5 cmp 0xc(%ebp),%eax 0x4014b8 jl 0x4014ca <printMaxTwo+30> 0x4014ba mov 0x8(%ebp),%eax 0x4014bd cmp 0x10(%ebp),%eax 0x4014c0 jl 0x4014ca <printMaxTwo+30> 0x4014c2 mov 0x8(%ebp),%eax 0x4014c5 cmp 0x14(%ebp),%eax 0x4014c8 jge 0x40150b <printMaxTwo+95> 0x4014ca mov 0xc(%ebp),%eax 0x4014cd cmp 0x8(%ebp),%eax 0x4014d0 jle 0x4014e2 <printMaxTwo+54> 0x4014d2 mov 0xc(%ebp),%eax 0x4014d5 cmp 0x10(%ebp),%eax 0x4014d8 jle 0x4014e2 <printMaxTwo+54> 0x4014da mov 0xc(%ebp),%eax 0x4014dd cmp 0x14(%ebp),%eax 0x4014e0 jg 0x401504 <printMaxTwo+88> 0x4014e2 mov 0x10(%ebp),%eax 0x4014e5 cmp 0x8(%ebp),%eax 0x4014e8 jle 0x4014ff <printMaxTwo+83> 0x4014ea mov 0x10(%ebp),%eax 0x4014ed cmp 0xc(%ebp),%eax 0x4014f0 jle 0x4014ff <printMaxTwo+83> 0x4014f2 mov 0x10(%ebp),%eax 0x4014f5 cmp 0x14(%ebp),%eax 0x4014f8 jle 0x4014ff <printMaxTwo+83> 0x4014fa mov 0x10(%ebp),%eax 0x4014fd jmp 0x401509 <printMaxTwo+93> 0x4014ff mov 0x14(%ebp),%eax 0x401502 jmp 0x401509 <printMaxTwo+93> 0x401504 mov 0xc(%ebp),%eax 0x401507 jmp 0x40150e <printMaxTwo+98> 0x401509 jmp 0x40150e <printMaxTwo+98> 0x40150b mov 0x8(%ebp),%eax 0x40150e mov %eax,0x4(%esp) 0x401512 movl $0x405064,(%esp) 0x401519 call 0x403bf0 <printf> 0x40151e nop 0x40151f leave 0x401520 ret
For the third one:
0x401521 push %ebp 0x401522 mov %esp,%ebp 0x401524 sub $0x18,%esp 0x401527 mov 0x8(%ebp),%eax 0x40152a cmp 0xc(%ebp),%eax 0x40152d jl 0x401554 <printMaxThree+51> 0x40152f mov 0x8(%ebp),%eax 0x401532 cmp 0x10(%ebp),%eax 0x401535 jl 0x401554 <printMaxThree+51> 0x401537 mov 0x8(%ebp),%eax 0x40153a cmp 0x14(%ebp),%eax 0x40153d jl 0x401554 <printMaxThree+51> 0x40153f mov 0x8(%ebp),%eax 0x401542 mov %eax,0x4(%esp) 0x401546 movl $0x405064,(%esp) 0x40154d call 0x403bf0 <printf> 0x401552 jmp 0x4015ba <printMaxThree+153> 0x401554 mov 0xc(%ebp),%eax 0x401557 cmp 0x8(%ebp),%eax 0x40155a jle 0x40157a <printMaxThree+89> 0x40155c mov 0xc(%ebp),%eax 0x40155f cmp 0x10(%ebp),%eax 0x401562 jle 0x40157a <printMaxThree+89> 0x401564 mov 0xc(%ebp),%eax 0x401567 cmp 0x14(%ebp),%eax 0x40156a jle 0x40157a <printMaxThree+89> 0x40156c movl $0x405068,(%esp) 0x401573 call 0x403bf0 <printf> 0x401578 jmp 0x4015ba <printMaxThree+153> 0x40157a mov 0x10(%ebp),%eax 0x40157d cmp 0x8(%ebp),%eax 0x401580 jle 0x4015a7 <printMaxThree+134> 0x401582 mov 0x10(%ebp),%eax 0x401585 cmp 0xc(%ebp),%eax 0x401588 jle 0x4015a7 <printMaxThree+134> 0x40158a mov 0x10(%ebp),%eax 0x40158d cmp 0x14(%ebp),%eax 0x401590 jle 0x4015a7 <printMaxThree+134> 0x401592 mov 0x10(%ebp),%eax 0x401595 mov %eax,0x4(%esp) 0x401599 movl $0x405064,(%esp) 0x4015a0 call 0x403bf0 <printf> 0x4015a5 jmp 0x4015ba <printMaxThree+153> 0x4015a7 mov 0x14(%ebp),%eax 0x4015aa mov %eax,0x4(%esp) 0x4015ae movl $0x405064,(%esp) 0x4015b5 call 0x403bf0 <printf> 0x4015ba nop 0x4015bb leave 0x4015bc ret
Apocalipsis Sorry,my english is bad. But I just want to say that this code: return((a>b?a:b)>(c>d?c:d)?(a>b?a:b):(c>d?c:d)); need more operators (4) to calculate than this code: a>b?(c>d?(c>a?c:a):(d>a?d:a)):(c>d?(c>b?c:b):(d>b?d:b)) need 3. And this code printf("%d\n", ((a>= b && a >= c && a >= d)?a:(b > a && b > c && b > d)?b:(c > a && c > b && c > d)?c:d)); need a lot more operators to calculate
Apocalipsis to return max=d with this code
return (a>b && a>c && a>d) ? a : (b>c && b>d) ? b : (c>d) ? c : d; the computer need to compare a with all other variables; then b with c,d; then c with d. So that need 6 operatorsalaniane My point is the use of ternary conditional operator does not provide any value other than bragadacio. The simplest code compiles cleaner with only 3 jump instructions. The ternary code requires 13 jump instructions. Best case scenario through the ternary code is 7 jump instructions. Best/Worst case for the first code is 3 jump instructions.
But, more importantly if you had to revise the original code to compare 5 integers instead of 4, it's easier to revise the first example. You just need to add another if statement. To revise the ternary conditional, you would have dig through the conditional and update each level of comparison with another && new condition. If you miss one, then you have a logic bug.
ranamk_kumar This seems to be the best explanation so far.Very well explained BTW how to get the assembly generated by the compiler?
anuragkumar19091 Hi,
I have one doubt here. In case of time complexity, suppose we put all the integers (can be 100 also and then find the max of them) in an array and then sort them in decreasing order using some best sorting method like merge sort which has time complexity of nlogn and then get the first index of the array to return the maximum integer. Will this approach be ok to implemet or your 1st solution is better than this approach?
abdelrahman_1151 Thanks ,it helped me alot.
benaffleks beautiful
raviyadav13652 int a, b, c, d; cin>>a>>b>>c>>d; if(a>b&a>c&a>d) {cout<a&b>c&b>d) {cout<a&c>b&c>d) { cout<
} else { cout<<d; } } }CHODHARY include
include
using namespace std; /* * * Prosen Ghosh * American International University - Bangladesh (AIUB) * */ int max_of_four(int a,int b,int c, int d){
if(a > b){ if(a > c){ if(a>d)return a; else return d; } else { if(c > d)return c; else return d; } } else{ if(b > c){ if(b > d)return b; else return d; } else{ if(c > d)return c; else return d; } }}
int main() {int a, b, c, d; scanf("%d %d %d %d", &a, &b, &c, &d); int ans = max_of_four(a, b, c, d); printf("%d", ans); return 0;}
jack_henry_lind1 This could not possibly be more inelegant.
maximshen Compact code sometimes is good, but Readability is also needed. I won't suggest anyone do this.
alex_kilias [deleted]
AdHominem This is not concise, but bad code and if you write code like this in a productive environment, your codebase will be utterly unmaintainable.
hacktik can u explain me the logic how that it executes in elaborated manner...?
ashkin great !!
Bad_Jim Real programmers can write perl in any language.
rahatchd return max(max(a,b),max(c,d))is a bit more readablesnanilim Its look pretty good
aanchal13111998 can get full code
sametyorukoglu int max_of_four(int a, int b, int c, int d){ return (max(max(a,b),max(c,d))); }
humanshapedhole also just one expression but a little bit more readable:
return (a>b && a>c && a>d) ? a : (b>c && b>d) ? b : (c>d) ? c : d;
glennlopez hey, can you tell me more about how ":" and "?" is used and what this is called in cpp. I wanna learn more about how to use this function
Bad_Jim That's the ternary operator. It works like this:
condition ? expression 1 : expression 2If the condition evaluates to true, the ternary operator gives you expression 1. If it is false, it gives you expression 2.
What he's doing there is chaining them together, so if the condition is false, it gets evaluated by the next ternary expression.
arleckse Thank you for the good explanation :) Very helpful!
micuemerson1 return max(a, max(b, max(c, d)));
more elegant one ;)
tarandeeps1197 I didnt get that one?Can you explain it?
lcbsanches Returns the lagest of all element. First: max(6,5) Second: max(4,6) And the laast one: max(3,6)
bindkamal yeah pretty cool. i did the same too. but its good when done for small logic. going to fail the readability aspect when used for big logics.
benrstraw For fun I tried something like this. Came up with:
int max_of_four(int a, int b, int c, int d) { return a>b?a>c?a>d?a:d:c>d?c:d:b>c?b>d?b:d:c>d?c:d; }
dtran18 horrendously fun
nit_2108 /* easily readable */ int max_of_four() { int x=0; int y=0;
for(int i=0;i<4;i++) { cin >> x; if(x>y) y=x; } return y;}
beijuchacha un...readable for me
___jaw___ return max(max(a, b), max(c,d));
ChanuChanu good (y)
keshavbans Its compact and logical. +1
kangkanlahkar1 I did this return fmax(a, fmax(b, fmax(c, d)));
codermandy More simplified version of this :-
int max_of_four(int a, int b, int c, int d){ int z=0; int t1=a>b?a:b; int t2=c>d?c:d; z=t1>t2?t1:t2; return z; }
shirodkarkalpes1 yes its simple thanks
omamak1998 Thanks :)
kevin_genus Doesn't mean a thing if it can't easily be read.
alaniane Try taking this code logic and your code logic and comparing what assembly code is generated:
int max_of_four(int a, int b, int c, int d){ int max = a;
if(b > max){ max = b; } if(c > max){ max = c; } if(d > max){ max = d; } return max;}
It may surprise you. Efficient code is at the assembly level not at the higher language level. If you confuse the compiler it will generate code that is a lot more inefficient.
beckwithdylan NOT SCALABLE
dang_tuthieu Me too return ((a>b?a:b)>(c>d?c:d)?(a>b?a:b):(c>d?c:d));
ayushkumar_agra1 This is very cool.One of the best optimized codes
Thirumagaldhivya nice logic
temur_nazli I really like it.
marcus_wong930 nah i use max(max(a, b), max(c, d))
adrianjmartin Always go for readability and let the compiler do the optimization for you
jere_davidson This is my Solution, pretty basic, but its based on proccess of elimination
int max_of_four(int a, int b, int c, int d){ int ans; if (a > b && a > c && a > d) ans = a; else if (b > c && b > d) ans = b; else if (c > d) ans = c; else ans = d; return ans; }
jen_1490 i like the neatness of it. everyone is using advanced methods to solve introductory-level problems, which isn't bad or against any rules, but it makes me feel as if they miss the point of doing basic code. btw, thank you. i just realized i was dragging my code out much further than i needed it to.
bhogayata_amrita [deleted]Akahaysharma4 same here
s11170031458 can u give me full code
s11170031458 can u give me full code
bhogayata_amrita what if the input integers are similiar. i mean what if a=3 and b=3 and both are max of all four entered integer?
Namadu Jere's code will still work. a > b will be false, but b > c && b > d will be true, so the value of b will be assigned to ans, then returned. We still end up with the 3 that we're looking for.
Most solutions to this problem will work just fine with duplicate values. It doesn't matter which variable the maximum value comes from; all we care about in this context is the value itself.
bhogayata_amrita Yes, I get it now! Thank you !!
jastirakesh1999 same here
amritanair254 How about:
int max_of_four(int a, int b, int c, int d){ int temp= 1-102224; if(temp<a){temp =a;} if(temp<b){temp =b;} if(temp<c){temp =c;} if(temp<d){temp =d;} return temp; }
phillipnguyen This isn't a bad idea, just needs some work:
int max_of_four(int a, int b, int c, int d) { int m = a; if (b > m) m = b; if (c > m) m = c; if (d > m) m = d; return m; }
wedersonsilva Your solution was what I expected from my mind. However I didn't make it. My code worked, but it was very messy.
Great solution, congrats for you. :-)
ay081298 its not running
ashutosh_ashain This Is best for understanding if-else loop...instead of terenary operator. Well terenary Operator Is short and Efficient.
RFzahid Here is how I did it :
int max_of_four(int a, int b, int c, int d){ int temp1, temp2; temp1 = (a > b) ? a : b; temp2 = (c > d) ? c : d; return ((temp1 > temp2) ? temp1 : temp2); }
THE_RV5 when I tried this same, it shows me test case fails. however my output is perfect. only problem at the submit time...!!!
THE_RV5 when I tried this same, it shows me test case fails. however my output is perfect. only problem at the submit time...!!!
dtran18 you might want to try to init temp1 and temp2 to 0;
int temp1, temp2; temp1 = temp2 = 0; temp1 = (a > b) ? a:b; temp2 = (c > d) ? c:d; return (temp1 > temp2) ? temp1:temp2;rupeshshukla123 no need to initialize it to zero ,Try this
int e =( a>=b?a:b);
int f =( c>=d?c:d);
return(e>=f?e:f);
wtian Actually, you can include the algorithm library, and then you can simply use oneline to get the maximum value
pete_programmer1 [deleted]1m2r3a I did something similar. int max_of_four(int a, int b, int c, int d) { int e = std::max(a,b); int f = std::max(c,d); return (e < f) ? f : e; }
DraigRygbi I prefer mine
int max_of_four(int a, int b, int c, int d){ return max(max(max(a,b),c),d); }
s_kostyuk Or event simplier (since C++11):
inline int max_of_four(int a, int b, int c, int d) { return std::max({a, b, c, d}); }
maggotfinger my solution without using sort or max function from the library:
int max_of_two(int a, int b){ return a > b ? a : b; } int max_of_four(int a, int b, int c, int d){ return max_of_two(max_of_two(a,b), max_of_two(c,d)); }
maggotfinger dont know why the 1st return statement double indents...
vacky11 Awesome!
d_veirs My super basic one:
int max_of_four(int a, int b, int c, int d){
if(a < b){ a = b; } if(a < c){ a = c; } if(a < d){ a = d; } return a;}
imraanpattan cool,you gave a smart logic
nevets_oomra I like your solution better. Readable, simple and short.
reic73 Here is my code.. hope it helps!! max : max value variable; max_t : temporary max value variable;
int max_of_four(int a, int b, int c, int d) { int num[4] ={a,b,c,d},i,max=0,max_t; for(i=0;i<4;i++){ max_t=max-num[i]; if (max_t<=0){ max=num[i]; } } return max; }
ankitparagshah return max(max(a,b),max(c,d));
Voley This is the nicest by far.
naveenkedilaya My function :
int max_of_four(int a, int b, int c, int d) { int max = a; if(b > max) max = b; if(c > max) max = c; if(d > max) max = d; return max; }
d_veirs It's incredible how many different ways there are of doing this, I figured the way I did it was the most basic and what everyone would try, but you are the first to post that is doing the same way i am, here is mine:
int max_of_four(int a, int b, int c, int d){
if(a < b){ a = b; } if(a < c){ a = c; } if(a < d){ a = d; } return a;}
naveenkedilaya Yes, this is good. But I tried to keep the values of a, b, c, d unchanged. So I used another variable max.
astroanu2004 what i did was add the numbers to a vector and sort. then return the last element.
nghaitai Yep thats what I did too.
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