1) i had wa35 with eps = 1e-15
2) i had wa82 with eps = 1e-11
3) ac with simple eps = 1e-9

I've already solved this problem in Pascal, but now I'm trying to get through with my C++ code. I see no difference to my accepted solution and interested, what the point.

Can someone help me to understand?

Compiled with Gnu C++ compiler.
#include <cstdio>
#include <vector>

#define ___MAXN 1000

typedef unsigned int uint;
std::vector< std::vector<int> > G(0);
int col[___MAXN] = {0};

void dfs(uint u, uint c)  {
    col[u] = c;
    for (uint v=0; v<G[u].size(); v++)
        if (!col[G[u][v]])
            dfs(G[u][v], 3-col[u]);
}

void colorize() {
    for (uint u=0; u<G.size(); u++)
        if (!col[u])
            dfs(u, 1);
}

int main()  {
    uint n;
    scanf("%u", &n);
    G.resize(n);

    for (uint i=0; i<n; i++) {
        static uint x;
        scanf("%u", &x);
        do  {
            G[i].push_back(x-1);
            scanf("%u", &x);
        }   while (x);
    }
    colorize();
    n = 0;
    for (uint i=0; i<G.size(); i++)
        switch (col[i]) {
        case 0:
            printf("0\n");
            return 0;
        case 1:
            n++;
            break;
        }
    printf("%u\n", n);
    char c = 0;
    for (uint i=0; i<G.size(); i++)
        if (col[i]==1)  {
            printf("%c%u", c, i+1);
            c = ' ';
        }
}

Is test 10 correct? A couple old AC solutions now have WA 10, and my new solution too.



Edited by author 29.04.2009 21:16

program Project1075_chala;

{$APPTYPE CONSOLE}

uses
  SysUtils, math;

  const
  EPS = 0.0000001;

    var
    xa, xb, xc, ya, yb, yc, za, zb, zc, r : integer;
    AB, BC, AC, cos_gamma, cos_gamma1, yoy, vatar, d, h : real;

begin
   read(xa, ya, za);
   read(xb, yb, zb);
   read(xc, yc, zc);
   read(r);
   AB := sqrt(sqr(xb-xa)+sqr(yb-ya)+sqr(zb-za));
   AC := sqrt(sqr(xc-xa)+sqr(yc-ya)+sqr(zc-za));
   BC := sqrt(sqr(xb-xc)+sqr(yb-yc)+sqr(zb-zc));
   if AB + BC <= AC+EPS then d := AB-2*r+PI*r
   else
     if (AC+EPS >= BC + AB) or (BC+EPS >= AC + AB) then d := AB
     else
       begin
         cos_gamma := (AC*AC+BC*BC-AB*AB)/(2*AC*BC);
         h := AC*BC*sqrt(1 - sqr(cos_gamma))/AB;
       if h+EPS >= r then d := AB
       else
         begin
           vatar := 2 * sqrt(sqr(r)-sqr(h));
           cos_gamma1 := (2*sqr(r)-sqr(vatar))/(2*r*r);
           yoy := arccos(cos_gamma1) * r;
           d := AB - vatar + yoy;
         end;
       end;
   writeLn(d:0:2);
end.

thanks

Cannot beat test 41.
Please share any ideas, tricky tests.

In my opinion, for n=4 the correct answer is 20 if I understood the condition of the problem correctly, i.e for n=3 there are exists 2 ways:
123231 and 132321. Please, explain me my mistake if I'm wrong.

What does it mean "to fall" into the gully?
Does it mean that the Pakhom's way intersects polyline ABC?

what is wrong in my solution?

Program N1744;
Var
n,i,j,t,k:integer;
A:array[1..100,1..100] of integer;
R:array[1..50000,1..3] of integer;
begin
  Readln(n);

  for i:=1 to N do
    for j:=1 to N do
    if i<>j then A[i,j]:=0 else A[i,j]:=3;

  k:=0;
  for i:=1 to N do
    for j:=1 to n do
      for t:=1 to n  do

      if (A[i,j]<3)and(A[i,t]<3) and(A[j,t]<3) then
      begin
      inc(k);
      R[k,1]:=i;
      R[k,2]:=j;
      R[k,3]:=t;
      inc(A[i,j]);
      inc(A[i,t]);
      inc(A[j,t]);
      inc(A[j,i]);
      inc(A[t,i]);
      inc(A[t,j]);
      end;
    writeln(k);

    for i:=1 to k do
      writeln(R[i,1],' ',R[i,2],' ',R[i,3]);
    Readln;
end.

is there a difference in what order the output numbers of soldiers?

Edited by author 24.01.2010 16:02

Edited by author 24.01.2010 16:03

I tried to use dynamic programming but failed.Who can tell me how to do it? Thank you very much!

here is my algo
#include <iostream>
#include<algorithm>
using namespace std;
int main()
{
const int N=50000;
int a[N],b[N],i,n,k,c[N],d[N],s=0;
bool p=true;
cin>>n;
for(i=0;i<n;i++)
cin>>a[i];
cin>>k;
int j=k-1;
for(i=0;i<k;i++)
cin>>b[i];
int x=0,y=0;
for(i=0;i<n;i++)
    c[x++]=a[i];
for(i=0;i<k;i++)
    d[y++]=b[i];
nth_element(c,c,c+n);
nth_element(d,d,d+k);
for(i=n-1;i>=0;i--)
{
    while(j>=0)
    {
        s=d[j]+c[i];
        j--;
        if(s==10000)
        {
        p=true;
        break;
        }
        else
            p=false;
    }
    if(p==true)
        break;

}
if(p==true)
{
    cout<<"YES"<<endl;
}
else
cout<<"NO"<<endl;
return 0;
}

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Why WA48? Please, give some tests.

Hello! I have the following task:

I have 2 groups: boys and girls. Each boy has a list of girls' names. The list contains girls he want to dance with. Each girl has the same list with boys' names. I khow, that the quantity of girls is not less, than the quantity of boys. I have to answer the question: are there pairs boy-girl (in each pair the guys want to dance with each other) when all girls will dance? Each list is not empty.

Please, give me an idea to solve this problem. Thank you.

Is string comparing case-sensitive?

I have a good hash function (I think), but i don`t know how to store the hash codes for fast access. please help

Edited by author 12.07.2009 06:39

Be careful!

The input string may contain spaces and/or line breaks!

uses
  SysUtils ,Math;

Var
  a, R:integer;
  s :Real;
begin
  ReadLn(a,R);
  If R > 0.5*a then
    S := pi*R*R + 2*a*sqrt(R*R-0.25*a*a) -4*R*R*arcCos(0.5*a/R);
  else S := pi * R*R;
  WriteLn(S :0:3);
end.

I passed the test in the problem.
But why I couldn't pass the  first test?
Here are my program:
var
  s,s2:string;
  n,i,j,k,l:longint;
  s1,c:array[1..50000]of string;
  m:array[1..100,1..100]of integer;
  b:boolean;
function xun(len:longint):boolean;
  var
    j:longint;
  begin
    if j=1
    then begin
           xun:=true;
           exit;
         end;
    for j:=len-1 downto 1 do
      begin
        if m[j,len]>0
        then begin
               if xun(j)
               then begin
                      write(s1[m[j,len]],' ');
                    end;
             end;
      end;
  end;
begin
  //assign(input,'1002.in');reset(input);
  readln(s);
  repeat
  l:=length(s);
  readln(n);
  for i:=1 to n do
    begin
      b:=false;
      readln(s1[i]);
      for j:=1 to length(s1[i]) do
        case s1[i][j] of
          'i','j':c[i]:=c[i]+'1';
          'a','b','c':c[i]:=c[i]+'2';
          'd','e','f':c[i]:=c[i]+'3';
          'g','h':c[i]:=c[i]+'4';
          'k','l':c[i]:=c[i]+'5';
          'm','n':c[i]:=c[i]+'6';
          'p','r','s':c[i]:=c[i]+'7';
          't','u','v':c[i]:=c[i]+'8';
          'w','x','y':c[i]:=c[i]+'9';
          'o','q','z':c[i]:=c[i]+'0';
        end;
      for j:=1 to l-length(c[i])+1 do
        begin
          s2:=copy(s,j,length(c[i]));
          if s2=c[i]
          then m[j,j+length(c[i])-1]:=i;
        end;
    end;
    for j:=length(s)-1 downto 1 do
      begin
        if m[j,length(s)]>0
        then begin
               if xun(j-1)
               then begin
                      b:=true;
                      write(s1[m[j,length(s)]]);
                      break;
                    end;
             end;
      end;
    if b=false
    then write('No solution.');
    readln(s);
    writeln;
      fillchar(s1,sizeof(s1),0);
      fillchar(c,sizeof(c),0);
      fillchar(m,sizeof(m),0);
  until s='-1';
  //close(input);
end.

4
14 13 14 13

the answer is 2!