Just try to replace x, y or z using equation y = x + z (vector form).
Count of cells on path is |x| + |y| + |z| + 1.

WA6?

Hi, I've solved the problem easily on C, but can't solve it on C# (almost the same code), getting Runtime Error on #2.
Can someone point out what's wrong in my code?

using System;

namespace Application
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] pos = new int[3];
            for(int i=0; i<n; i++)
            {
                string[] s = Console.ReadLine().Split(' ');
                int ind = s[0][0] - 'X';
                pos[ind] += int.Parse(s[1]);
            }

            while(true)
            {
                if(pos[0] * pos[2] > 0)
                {
                    int sign = pos[0] / Math.Abs(pos[0]);
                    int min = Math.Min(Math.Abs(pos[0]), Math.Abs(pos[2]));
                    pos[0] -= sign * min;
                    pos[1] += sign * min;
                    pos[2] -= sign * min;
                }
                else if(pos[0] * pos[1] < 0)
                {
                    int sign = pos[0] / Math.Abs(pos[0]);
                    int min = Math.Min(Math.Abs(pos[0]), Math.Abs(pos[1]));
                    pos[0] -= sign * min;
                    pos[1] += sign * min;
                    pos[2] -= sign * min;
                }
                else if(pos[1] * pos[2] < 0)
                {
                    int sign = pos[2] / Math.Abs(pos[2]);
                    int min = Math.Min(Math.Abs(pos[1]), Math.Abs(pos[2]));
                    pos[0] -= sign * min;
                    pos[1] += sign * min;
                    pos[2] -= sign * min;
                }
                else
                {
                    break;
                }
            }
            int nOfDir = 0;
            if(pos[0] != 0)
                nOfDir++;
            if(pos[1] != 0)
                nOfDir++;
            if(pos[2] != 0)
                nOfDir++;
            Console.WriteLine(nOfDir);
            if(pos[0] != 0)
                Console.WriteLine("X " + (-pos[0]).ToString());
            if(pos[1] != 0)
                Console.WriteLine("Y " + (-pos[1]).ToString());
            if(pos[2] != 0)
                Console.WriteLine("Z " + (-pos[2]).ToString());
        }
    }
}

Wrong answer 8, give me some tests, please!

- Calculate the x y coordinates of the student
- Find the X, Y or Z axis nearest to the student (the axis that the student can go on it with least step).
- Calculate the number of steps to nearest axis + the number of steps from new place in nearest axis to central cell.

Note:
On X axis : x = 0
On Y axis : x = y
On Z axis : x = -y
Least steps to X: x + step * xDir = 0                   => step = ?
Least steps to Y: x + step * xDir = y + step * yDir     => step = ?
Least steps to Z: x + step * xDir = - (y + step * yDir) => step = ?

Of which:
X axis : (xDir, yDir) = (0,2)
Y axis : (xDir, yDir) = (1,1)
Z axis : (xDir, yDir) = (1,-1)

Chúc các bạn may mắn :)

Edited by author 09.02.2011 09:40

Edited by author 09.02.2011 09:41

program ural;
uses math;
var s:array['X'..'Z']of integer;
    c:char;
    d,n,i:integer;
begin
  readln(n);
  for i:=1 to n do
    begin
      read(c);
      readln(d);
      s[c]:=s[c]+d;
    end;
  if(s['X']>0)and(s['Z']>0)then
    begin
      d:=min(s['X'],s['Z']);
      inc(s['Y'],d);
      dec(s['X'],d);
      dec(s['Z'],d);
    end
  else
    if(s['X']<0)and(s['Z']<0)then
      begin
        d:=max(s['X'],s['Z']);
        inc(s['Y'],d);
        dec(s['X'],d);
        dec(s['Z'],d);
      end;
  if(s['X']>0)and(s['Y']<0)then
    begin
      d:=max(-s['X'],s['Y']);
      inc(s['Z'],d);
      inc(s['X'],d);
      dec(s['Y'],d);
    end
  else
    if(s['X']<0)and(s['Y']>0)then
      begin
        d:=min(-s['X'],s['Y']);
        inc(s['Z'],d);
        inc(s['X'],d);
        dec(s['Y'],d);
      end;
  if(s['Z']>0)and(s['Y']<0)then
    begin
      d:=max(-s['Z'],s['Y']);
      inc(s['X'],d);
      inc(s['Z'],d);
      dec(s['Y'],d);
    end
  else
    if(s['Z']<0)and(s['Y']>0)then
      begin
        d:=min(-s['Z'],s['Y']);
        inc(s['X'],d);
        inc(s['Z'],d);
        dec(s['Y'],d);
      end;
  writeln(abs(s['X'])+abs(s['Y'])+abs(s['Z']));
  if s['X']<>0 then
    writeln('X ',-s['X']);
  if s['Y']<>0 then
    writeln('Y ',-s['Y']);
  if s['Z']<>0 then
    writeln('Z ',-s['Z']);
end.

I have only two coordinates on a plane, and just read input. Nothing more and my prog works 0,046 sec. But in statistics there are AC's in 0,001 sec.

I wonder how can it be???

It really hard to understand the meaning of the description of this problem!It took me an hour and more!

I think the way to solve this prob is convert to Dekart coordinate-system.
Below is my solution, I got WA at test #2 >.<.

var
  nowX: longint;
  nowY: longint;
{--------------------------------------------------------}
procedure moveX(lengths: longint);
begin
  nowX:= nowX + lengths;
end;
{--------------------------------------------------------}
procedure moveY(lengths: longint);
begin
  nowY:= nowY + lengths;
end;
{--------------------------------------------------------}
procedure move(section: integer; direction: char; lengths: longint);
var
  tmp: longint;
begin
  case direction of
    'X': begin
      case section of
        1: if (nowX + lengths < 0) then
           begin
             tmp:= nowX;
             moveX(-nowX);
             move(2, 'X', lengths + tmp);
           end
           else moveX(lengths);
        4: if (nowX + lengths < 0) then
           begin
             tmp:= nowX;
             moveX(-nowX);
             move(2, 'X', lengths + tmp);
           end
           else moveX(lengths);
        2: if (nowX + lengths > 0) then
           begin
             tmp:= nowX;
             move(2, 'X', -nowX);
             move(1, 'X', lengths + tmp);
           end
           else begin
             moveX(lengths);
             moveY(lengths);
           end;
        3: if (nowX + lengths > 0) then
           begin
             tmp:= nowX;
             move(3, 'X', -nowX);
             move(4, 'X', lengths + tmp);
           end
           else begin
             moveX(lengths);
             moveY(lengths);
           end;
      end;
    end;
    'Y': begin
      moveY(lengths);
    end;
    'Z': begin
      case section of
        1: if (nowX - lengths < 0) then
           begin
             tmp:= nowX;
             move(1, 'Z', nowX);
             move(2, 'Z', lengths - tmp);
           end
           else begin
             moveX(-lengths);
             moveY(lengths);
           end;
        4: if (nowY + lengths > 0) then
           begin
             tmp:= nowY;
             move(4, 'Z', -nowY);
             move(1, 'Z', lengths + tmp);
           end
           else begin
             if (nowX - lengths < 0) then
             begin
               tmp:= nowX;
               move(4, 'Z', nowX);
               move(3, 'Z', lengths - tmp);
             end
             else begin
               moveX(-lengths);
               moveY(lengths);
             end;
           end;
        2: if (nowX - lengths > 0) then
           begin
             tmp:= nowX;
             move(2, 'Z', nowX);
             move(1, 'Z', lengths - tmp);
           end
           else moveX(-lengths);
        3: if (nowX - lengths > 0) then
           begin
             tmp:= nowX;
             move(3, 'Z', nowX);
             move(4, 'Z', lengths - tmp);
           end
           else moveX(-lengths);
      end;
    end;
  end;
end;
{--------------------------------------------------------}
function getNowSection: integer;
begin
  if (nowX < 0) then
  begin
    if (nowY < 0) then exit(3)
    else exit(2);
  end
  else begin
    if (nowY < 0) then exit(4)
    else exit(1);
  end;
end;
{--------------------------------------------------------}
procedure readInput;
var
  i: integer;
  n: integer;
  dir: char;
  len: longint;
begin
  readln(n);
  for i:= 1 to n do
  begin
    readln(dir, len);
    move(getNowSection, dir, len);
  end;
end;
{--------------------------------------------------------}
procedure writeOutput;
begin
  if (nowX = 0) and (nowY = 0) then
  begin
    write(0);
    exit;
  end;
  if (nowX = 0) then
  begin
    writeln(1);
    write('Y ', -nowY);
    exit;
  end;
  if (nowY = 0) then
  begin
    writeln(1);
    if (nowX > 0) then write('X ', -nowX)
    else write('Z ', nowX);
    exit;
  end;
  writeln(2);
  case getNowSection of
    1: begin
      writeln('X ', -nowX);
      write('Y ', -nowY);
    end;
    2: begin
      writeln('Z ', nowX);
      write('Y ', -nowY);
    end;
    3: begin
      if (nowX = nowY) then write('X ', -nowY)
      else if (nowX < nowY) then
           begin
             writeln('X ', -nowY);
             move(3, 'X', -nowY);
             writeln('Z ', nowX);
           end
           else begin
             writeln('X ', -nowX);
             move(3, 'X', -nowX);
             write('Y ', -nowY);
           end;
    end;
    4: begin
      if (nowX = abs(nowY)) then write('Z ', nowX)
      else if (nowX < abs(nowY)) then
           begin
             writeln('Z ', nowX);
             move(4, 'Z', nowX);
             write('Y ', -nowY);
           end
           else begin
             writeln('Z ', -nowY);
             move(4, 'Z', nowY);
             write('X ', -nowX);
           end;
    end;
  end;
end;
{--------------------------------------------------------}
begin
  readInput;
  writeOutput;
end.

I just can't find where's mistake - i always get WA at test #1:

#include<iostream>
#include<string>
#include<vector>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<set>
#define REP(i,n) for(int i=0;i<n;i++)
#define REPD(i,n) for(int i=n;i>-1;i--)
#define FOR(i,j,k) for(int i=j;i<k;i++)
#define FORD(i,j,k) for(int i=j;i>k;i--)
#define PB push_back

using namespace std;


int main()
{
    int n;
    cin>>n;

    int X=0,Y=0,Z=0;

    REP(i,n)
    {
            char a;int p;
            cin>>a;cin>>p;
            if(a=='X') X+=p;
             else if(a=='Y') Y+=p;
              else Z+=p;
    }
    X+=Y;Z+=Y;

    if(X==0&&Z==0) cout<<"0"<<endl;

    else if(X==0) { cout<<"1"<<endl;cout<<"Z: "<<(-1)*Z<<endl;}
    else if(Z==0){ cout<<"1"<<endl; cout<<"X: "<<(-1)*X<<endl;}
    else if(abs(X)==abs(Z)) { cout<<"1"<<endl;cout<<"Y: "<<(-1)*X<<endl;}
  else  if(X>0&&Z>0)
    {
        int minimum=X+Z;
    int a=min(X,Z);

            if(X<Z)
            { cout<<"2"<<endl;
                     cout<<"Y: "<<(-1)*a<<endl;
                     cout<<"Z: "<<(-1)*(Z-a)<<endl;
            }
            else
             { cout<<"2"<<endl;
                     cout<<"X: "<<(-1)*(X-a)<<endl;
                     cout<<"Y: "<<(-1)*a<<endl;
            }
    }
    else if(X<0&&Z<0)
    {
          int minimum=X+Z;
          int a=abs(max(X,Z));
                if(X<Z)
            {
                       cout<<"2"<<endl;
                       cout<<"X: "<<(-1)*(X+a)<<endl;
                     cout<<"Y: "<<a<<endl;
            }
            else
             { cout<<"2"<<endl;
                     cout<<"Y: "<<a<<endl;
                     cout<<"Z: "<<(-1)*(Z+a)<<endl;
            }

    }
    else
    { cout<<"2"<<endl;
             cout<<"X: "<<(-1)*X<<endl;
                     cout<<"Z: "<<(-1)*Z<<endl;
    }

    int p;cin>>p;

}

  According to the problem describe,the text's answer should be:
y -2
Z -2
and my AC program produce this answer.
Is there something wrong?

Hello, world! I've solved this problem using representation triangle coordinates as ortogonal Dekart coordinates. Especially pay attention at the test
3
X 45
Z 45
Y -45
The answer must be ZERO:
0

var
  x,y,z:integer;
  n,i,j:integer;
  na,nx,ny,nz,nj:integer;
  c:char;
begin
  x:=0;y:=0;z:=0;
  readln(n);
  for i:=1 to n do
  begin
    readln(c,j);
    case upcase(c) of
      'X':inc(x,j);
      'Y':inc(y,j);
      'Z':inc(z,j);
    end;
  end;
  nx:=0;ny:=y+x;nz:=z-x;nj:=abs(nx)+abs(ny)+abs(nz);
  if (ny=0) or (nz=0) then na:=1 else na:=2;
  x:=nx+ny;y:=0;z:=nz+ny;j:=abs(x)+abs(y)+abs(z);
  if (x=0) or (z=0) then n:=1 else n:=2;
  if nj>j then
  begin
    na:=n;nx:=x;ny:=y;nz:=z;nj:=j;
  end;
  x:=nx-nz;y:=ny+nz;z:=0;j:=abs(x)+abs(y)+abs(z);
  if (x=0) or (y=0) then n:=1 else n:=2;
  if nj>j then
  begin
    na:=n;nx:=x;ny:=y;nz:=z;nj:=j;
  end;
  writeln(na);
  if nx<>0 then writeln('X ',-nx);
  if ny<>0 then writeln('Y ',-ny);
  if nz<>0 then writeln('Z ',-nz);
end.

Edited by author 10.07.2004 14:27

i submit my program,but the status is always "running"
now i have no idea about it,maybe something is wrong with the judge?
here is my program:

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <ctype.h>

int x=0,y=0,z=0;

void eliminate_x(){
    y+=x,z-=x,x=0;
}

void eliminate_y(){
    x+=y,z+=y,y=0;
}

void eliminate_z(){
    x-=z,y+=z,z=0;
}

int main()
{
    int i,n,step,type=0,min,m;
    char c;
    //freopen("test.in","r",stdin);
    scanf("%d",&n);
    for(i=0;i<n;i++){
        c=0;
        while(!isalpha(c)) c=getchar();
        scanf("%d",&step);
        if (c=='X') x+=step;
        else if (c=='Y') y+=step;
        else if (c=='Z') x-=step,y+=step;
    }
    min=abs(x)+abs(y);
    eliminate_x();
    if (abs(y)+abs(z)<min) min=abs(y)+abs(z),type=1;
    eliminate_y();
    if (abs(x)+abs(z)<min) min=abs(x)+abs(z),type=2;
    m=0;
    if (type==0){
        eliminate_z();
        if (!x) m++;
        if (!y) m++;
        printf("%d\n",m);
        if (x) printf("X %d\n",-x);
        if (y) printf("Y %d\n",-y);
    }else if (type==1){
        eliminate_x();
        if (!y) m++;
        if (!z) m++;
        printf("%d\n",m);
        if (y) printf("Y %d\n",-y);
        if (z) printf("Z %d\n",-z);
    }else{
        if (!x) m++;
        if (!z) m++;
        printf("%d\n",m);
        if (x) printf("X %d\n",-x);
        if (z) printf("Z %d\n",-z);
    }
    return 0;
}