For further help with Coding Bat (Java), please check out my books. I am also available for tutoring.
In the Logic-1 section of CodingBat the pace picks up a bit. None of the exercises should make you break a sweat, but it’s quite easy to write unnecessarily convoluted if/else statements. Many of my solutions make use of the ternary operator to save some vertical space and increase readability.
All 24 solutions were successfully tested on 4 February 2013.
cigarParty:
public boolean cigarParty(int cigars, boolean isWeekend) {
if (isWeekend) return (cigars >= 40);
return cigars >= 40 && cigars <= 60;
}
[/sourcecode]
<b>dateFashion:</b>
[sourcecode language="Java" gutter="false"]
public int dateFashion(int you, int date) {
if (you <= 2 || date <= 2) return 0;
return (you >= 8 && date >= 2 || date >= 8 && you >= 2) ? 2 : 1;
}
squirrelPlay:
public boolean squirrelPlay(int temp, boolean isSummer) {
return (isSummer) ? (temp >= 60 && temp <= 100)
: (temp >= 60 && temp <= 90);
}
[/sourcecode]
<b>caughtSpeeding:</b>
[sourcecode language="Java" gutter="false"]
public int caughtSpeeding(int speed, boolean isBirthday) {
if (isBirthday) speed -= 5;
if (speed <= 60) return 0;
return (speed > 60 && speed <= 80) ? 1 : 2;
}
[/sourcecode]
<b>sortaSum:</b>
[sourcecode language="Java" gutter="false"]
public int sortaSum(int a, int b) {
return (a + b >= 10 && a + b <= 19) ? 20 : a + b;
}
[/sourcecode]
<b>alarmClock:</b>
[sourcecode language="Java" gutter="false"]
if (vacation) return (day >= 1 && day <= 5) ? "10:00" : "off";
return (day >= 1 && day <= 5) ? "7:00" : "10:00";
[/sourcecode]
If you think this is too concise, then compare it with a solution that avoids the ternary operator:
[sourcecode language="Java" gutter="false"]
public String alarmClock(int day, boolean vacation) {
if (vacation) {
if (day >= 1 && day <= 5)
return "10:00";
return "off";
}
if (day >= 1 && day <= 5)
return "7:00";
return "10:00";
}
[/sourcecode]
Ugly, isn't it?
<b>love6:</b>
[sourcecode language="Java" gutter="false"]
public boolean love6(int a, int b) {
return a == 6 || b == 6 || a + b == 6 || Math.abs(a - b) == 6;
}in1To10:
public boolean in1To10(int n, boolean outsideMode) {
return (outsideMode) ? n <= 1 || n >= 10 : n >= 1 && n <= 10;
}
[/sourcecode]nearTen:
public boolean nearTen(int num) {
return num % 10 >= 8 || num % 10 <= 2;
}
[/sourcecode]teenSum:
public int teenSum(int a, int b) {
return (a >= 13 && a <= 19 || b >= 13 && b <= 19) ? 19 : a + b;
}
[/sourcecode]
For further help with Coding Bat (Java), please check out my books. I am also available for tutoring.
In in1To10 could you explain your return?
return (outsideMode) ? n = 10 : n >= 1 && n <= 10;
Mostly the "?" and ":" those are new to me?
That’s the so-called ternary operator, which is a shorthand for if-then-else. I’m personally divided on its usage, since you trade succinctness for readability.
Here was my solution to the in1To10 problem
public boolean in1To10(int n, boolean outsideMode) {
return (outsideMode ? outside(n) : inside(n));
}
public boolean inside(int a){
return (a >= 1 && a <= 10 ? true : false);
}
public boolean outside(int a){
return (a = 10 ? true : false);
}
nearTen:
return (num+2)%10<5;
As you can see, supposedly clever solutions are not always the most readable.
Hi, here’s my code using no shorthands. Please excuse bad spacing.
public boolean in1To10(int n, boolean outsideMode) {
if (outsideMode){
if (n = 10) return true;
else return false;
} else {
if (n >=1 && n <= 10) return true;
else return false;
}
}
Well for some reason my post submission cut off some of my code. Here’s a pastebin link.
http://pastebin.com/TjEDSSSD
Without if two liner solution in java for Logic-1 > caughtSpeeding
public int caughtSpeeding(int speed, boolean isBirthday) {
int add = isBirthday ? 5 : 0;
return speed = 81 + add ? 2 : 1;
}
found an easier solution to dateFashion:
public int dateFashion(int you, int date) {
if(you <= 2 || date = 8 || date >= 8) return 2;
else return 1;
}
public int dateFashion(int you, int date) {
if(you <= 2 || date = 8 || date >= 8) return 2;
else return 1;
}
it messed it up idk why
no logic – thats why
solution
public int dateFashion(int you, int date) {
if(you<3 || date7 || date>7) return 2;
return 1;
}
Really learned a lot from your samples, Gregor Ulm. Thanks for your solutions.
I am able to solve codingbat however your solutions are much simpler.
public boolean specialEleven(int n) {
return (n%11==0 || n%11==1);
}