10517 - Wind of Change!

[lowai]

i use the following formula to calculate the latitude

Code: Select all

        m cos(n/R) - n
tan a = --------------
          m sin(n/R)

can anyone tell me what are the situations that i should output 'invalid or impossible'?

[mbakht]

If any of the two conditions is false:

1. n < 1001

2. a >= 0 && a <= 70

[lowai]

i still got WA.
[pascal]
const R = 6378.0;
var
i, kase : integer;
n, m : double;
a, t1, t2 : double;
begin
readln(kase);
for i := 1 to kase do
begin
readln(n, m);
write('Case ', i, ': ');
if (n >= 1001) or (n >= m) then
begin
writeln('Invalid or impossible.');
continue;
end;
t1 := m * cos(n / R);
if t1 < n then
begin
writeln('Invalid or impossible.');
continue;
end;
if abs(n) < 1e-7 then
begin
writeln('Invalid or impossible.');
continue;
end;
t2 := m * sin(n / R);
t1 := (t1 - n) / t2;
a := arctan(t1);
a := a * 180 / pi;

if a > 70 then
begin
writeln('Invalid or impossible.');
continue;
end;

write(trunc(a), ' deg ');
a := frac(a);
a := a * 60;
write(trunc(a), ' min ');
a := frac(a);
a := a * 60;
writeln(round(a), ' sec');
end;
end.
[/pascal]

[Faizur]

I also get wa with the same formula.
pls give some typical i/o .........

[Jalal]

It may also happened i u dont take all the variables in double
my 1st code with long (deg, min) proved WA

[Faizur]

I use double ..But again WA

Code: Select all

Sorrry, Code has been removed :lol: 

[the LA-Z-BOy]

at first thanks to mehedi bakht bhai...

If any of the two conditions is false:
1. n < 1001
2. a >= 0 && a <= 70

i was missing the first one.

to Faizur...
your first invalid condition checking is not right

Code: Select all

         if(n>1009.9) 
         { 
      printf("Invalid or impossible.\n"); 
      continue; 
         } 

rather it should be

Code: Select all

         if(n>=1001.0) 
         { 
      printf("Invalid or impossible.\n"); 
      i++;
      continue; 
         } 

and you also missed the i++ stuff here.
try to use degree minute second in int rather than double to avoid precision errors...

Code: Select all

          else 
          { 
        angle*=(180/pi); 
        int dg = (int)angle;
        min=angle-(long)angle; 
        min*=60;
        int mn = (int)min;
        sec=min-(long)min; 
        sec*=60; 
        int sc = (int)(sec+0.5);     // sec should be rounded
        printf("%d deg %d min %d sec\n",dg,mn,sc); 
          } 

Greetings...

[htl]

I think it's the precision prob. But I'm so confused that how do I get the integer part of a floating-point number. Can someone help me??
[c]
#include<stdio.h>
#include<math.h>
void main(void)
{
int count,x;
double n,m,pi,theta,a,b,angle;
pi=2*acos(0);
scanf("%d",&count);
for(x=1;x<=count;x++)
{
scanf("%lf %lf",&n,&m);
printf("Case %d: ",x);
theta=n/6378,a=m*cos(theta)-n,b=m*sin(theta);
if(n>=1001 || a<0 || (angle=atan(a/b)*180/pi)<0 || angle>70)
printf("Invalid or impossible.\n");
else
{
printf("%ld deg ",(long)angle);
angle=angle-(long)angle,angle*=60;
printf("%ld min ",(long)angle);
angle=angle-(long)angle,angle*=60;
printf("%.0lf sec\n",(long)angle);
}
}
}
[/c]

[the LA-Z-BOy]

try calculating the second part of the lat. in integer...
[cpp] else
{
printf("%ld deg ",(long)angle);
angle=angle-(long)angle,angle*=60;
printf("%ld min ",(long)angle);
angle=angle-(long)angle,angle*=60;
int sec = (int)(angle+0.5); // second in int + rounding
printf("%d sec\n",sec);
} [/cpp]
Greetings...

[Faizur]

Thanks a lot to the LA-Z-BOy .I get AC at last.
greetings...

[the LA-Z-BOy]

to lowai...
use
[pascal] write(trunc(a), ' deg ');
a := frac(a);
a := a * 60;
write(trunc(a), ' min ');
a := frac(a);
a := a * 60;
a := a+0.5;
writeln(trunc(a), ' sec'); [/pascal]
for output of `second' instead.
thanks.

[htl]

It really works!!

Thanks very much for teaching another method of rounding!

[w k]

Could You post some I/O?

Wojciech