Codeforces Beta Round #79(Div.2) Report

I feel frustrated.

A:I had some reading miss.However, 0:24,Pretest Passed.

B&C, all i have to do is coding. B,0:39 and C,0:57,Pretest Passed.

I also can solved E. 1:33,Pretest Passed. However, this source occurred overflow. So, I use 64-bit integer, it's correct(after contest). In this article, E's source is correct.

I explain E's algorithm.

Regard vectors A,B,C as complex number. Then, rotate or add C, we can get next number.

i(i(i(i…(i(A+n1C)+n2C)+n3C)+…)+nkC

Calculate it and use i^2=-1,

(i^m)A+NC+iN'C

is equals to B. (m=0,1,2,3)

Then,

B-(i^m)A=CN+iCN' .

Solve this eq. about N,N'. If they are Integer, Yes. 

Result:2404,216/1015.This round show a little easy.

[A]

#include<stdio.h>

#include<string.h>

#define NUM 100

int main(void){

  int m,n;

  int price[NUM];

  int i,j,k,l;

  int min=-1;

  short match[NUM][NUM];

  memset(match,-1,sizeof(match));

  scanf("%d %d",&n,&m);

  for(i=0;i<n;i++) scanf("%d",&price[i]);

  for(i=0;i<m;i++){

    scanf("%d %d",&j,&k);

    match[j-1][k-1]=1;

    match[k-1][j-1]=1;

  }

  for(i=1;i<=n;i++){

    for(j=i+1;j<=n;j++){

      if(match[i-1][j-1]<0) continue;

      for(k=j+1;k<=n;k++){

if(match[j-1][k-1]<0) continue;

if(match[i-1][k-1]<0) continue;

if(min<0 || min>price[i-1]+price[j-1]+price[k-1]) min=price[i-1]+price[j-1]+price[k-1];

      }

    }

  }

  printf("%d\n",min);

  return 0;

}

[B]

#include<stdio.h>

#include<string.h>

#define LENGTH 100001

int main(void){

  int count[10];

  char num[LENGTH];

  int i,j,k,l,times=0,sum;

  scanf("%s",num);

  for(i=0;i<10;i++) count[i]=0;

  l=strlen(num);

  if(l==1){

    puts("0");

    return 0;

  }

  for(i=0;i<l;i++) count[num[i]-'0']++;

  times=1;

  while(1){

    for(i=0,k=0;i<10;i++) k+=count[i];

    if(k<=1) break;

    for(i=0,sum=0;i<10;i++) sum+=i*count[i];

    sprintf(num,"%d\0",sum);

    l=strlen(num);

    for(i=0;i<10;i++) count[i]=0;

    for(i=0;i<l;i++) count[num[i]-'0']++;

    times++;

  }

  printf("%d\n",times-1);

  return 0;

}

[C]

#include<stdio.h>

#include<string.h>

#define LEN 100001

int main(void){

  char str[LEN],out[LEN];

  int m,n,i,j,k,l,min,minch;

  int count[26],c=0;

  memset(count,0,sizeof(count));

  scanf("%s%*c",str);

  scanf("%d",&k);

  l=strlen(str);

  for(i=0;i<l;i++) count[str[i]-'a']++;

  while(1){

    min=LEN;

    for(i=0;i<26;i++){

      if(count[i]==0) continue;

      if(min>count[i]){

min=count[i];

minch=i;

      }

    }

    if(k<min || min==LEN) break;

    k-=min;

    count[minch]=0;

  }

  for(i=0;i<26;i++) c+=(count[i]!=0);

  

  for(i=0,j=0;i<l;i++){

    if(count[str[i]-'a']==0) continue;

    out[j++]=str[i];

  }

  out[j]='\0';

  printf("%d\n",c);

  puts(out);

  return 0;

}

[E]

#include<stdio.h>

int answer(long long int  bx,long long int  by,long long int  cx,long long int  cy);

int main(void){

  struct vector{

    long long int  x;

    long long int  y;

  }a,b,c,d;

  int flg,j,k;

  

  scanf("%I64d %I64d",&a.x,&a.y);

  scanf("%I64d %I64d",&b.x,&b.y);

  scanf("%I64d %I64d",&c.x,&c.y);

  flg=0;

  flg+=answer(b.x-a.x,b.y-a.y,c.x,c.y);

  flg+=answer(b.x+a.y,b.y-a.x,c.x,c.y);

  flg+=answer(b.x+a.x,b.y+a.y,c.x,c.y);

  flg+=answer(b.x-a.y,b.y+a.x,c.x,c.y);

  if(flg==0) puts("NO");

  else puts("YES");

  return 0;

}

int answer(long long int  bx,long long int  by,long long int  cx,long long int  cy){

  long long int  tmp;

  if(cx==0 && cy==0){

    if(bx==0 && by==0) return 1;

    return 0;

  }

  if(cx==0){

    if(bx%cy==0 && by%cy==0) return 1;

    return 0;

  }else if(cy==0){

    if(bx%cx==0 && by%cx==0) return 1;

    return 0;

  }else{

    tmp=cx*cx+cy*cy;

    if((bx*cx+by*cy)%tmp==0 && (by*cx-bx*cy)%tmp==0) return 1;

    return 0;

  }

  return 0;

}