i also got wa on 5 and then found out i considered room and floor both can be at most 100. but problem says floor is 100 and room can be at most 500.

My answers are fully identical to the given one. But I have WA#1.
Maybe, are there some format-specified features?

Try this:
1 1 -1

ans: 1 3

Why are not correct
12
4
6 3 1 1

1) (())(())(()) =>3
2) (())(()))))(() =>0
3) )))(()(()))((( =>2
4) )))))((()))))((((((( =>1
5) )()()()()()()()(())( =>9
6) ))(()( =>1

try
1 3
-80000 0 80000

I get WA 13 again and again and I can not find a mistake. My main logic looks like this:
for(j=0;j<n;j++)
{l=(x[j]-X)*(x[j]-X)+(y[j]-Y)*(y[j]-Y)+(z[j]-Z)*(z[j]-Z);
if (l-D<1e-10) D=l;}
printf("%0.6f\n",acos((2-D)/2.0)*r);

I believe it is correct..So can anybody help me with finding a bug, please? Does anyone have a same problem?

Please, somebody, give the 4th test

Give that test, pls...

What an amusing problem! Now it seems to be easy - in contrast to prima facie :^) Special thanks to Vorokh Sergey and Mamonov Anton, who proved correctness of my solution.

And some test data

input #1:
0 0 90 5
5 4.9
output #1:
28.2176

input #2:
0 0 90 5
0 -0.000001
output #2:
31.4159

I can't understand why. Can anybody help me?

try this:
aaaba

is
2
aa aba

not
3
aaa b a

WA #7 can anyone help plz?

using simple dp

var
 AD,AC,BD,BC,X,Y:int64;
 CD:real;

BEGIN
 read(AD,AC,BD,BC);

 X:=AD*AC-BD*BC;
 Y:=AD*AC*(BD*BD+BC*BC)-BD*BC*(AD*AD+AC*AC);
 if(X=0)or(Y*X<0) then write('Impossible.')
 else begin
  write('Distance is ');
  CD:=1000*sqrt(Y/X);
  write(CD:0:0,' km.');
 end;
END.

Why Wa18? What is test?

Why Runtime Error?

#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
int main() {
    unsigned short n, m;
    scanf("%hu", &n);
    vector <unsigned long long> bytes(n);
    vector <vector<unsigned short> > red(n);
    for(unsigned short i=0;i<n;i++) scanf("%llu", &bytes[i]);
    for(unsigned short i=1;i<n;i++) {
        unsigned short x, y;
        scanf("%hu %hu", &x, &y);
        red[x-1].push_back(y);
        red[y-1].push_back(x); }
    if(n>1) {
        for(unsigned short i=0;i<red.size();i++) sort(red[i].begin(), red[i].end());
        for(unsigned short i=0;i<red.size();i++) {
            for(unsigned short j=0;j<red[i].size()-1;j++) {
                if(red[i][j]==red[i][j+1]) {
                    for(unsigned short pos=j+1;pos<red[i].size()-1;pos++) red[i][pos] = red[i][pos+1];
                    red[i].pop_back(); }
            }
        }
    }
    scanf("%hu", &m);
    for(int i=0;i<m;i++) {
        unsigned short v, t;
        scanf("%hu %hu", &t, &v);
        if(t==1) {
            for(unsigned j=0;j<red[v-1].size();j++) bytes[red[v-1][j]-1] += bytes[v-1]; }
        if(t==2) printf("%llu\n", bytes[v-1]%1000000007); }
}

I use a simple DP ,but WA#10.Give me some useful tests,pls.
And I'd like to know if there is a better algo.

Recursive solution works fine! If you are getting TLE, Rethink your DP state :)