Submission #918326

#	Time	Username	Problem	Language	Result	Execution time	Memory
918326		contest_alt	Gondola (IOI14_gondola)	C++17	100 / 100	20 ms	3560 KiB

gondola

#include "gondola.h"

#include <algorithm>
#include <vector>
#include <stdio.h>

int valid( int n, int inputSeq[] ) {
  int shift_min = n, shift_max = -1;

  std::vector<int> vals( n );
  
  for( int i = 0 ; i < n ; i++ ){
    vals[i] = inputSeq[i];

    if( inputSeq[i] > n )
      continue;

    if( inputSeq[i] <= 0 )
      return false;

    int shift = (inputSeq[i] - 1 + n - i) % n;

    shift_min = std::min( shift_min, shift );
    shift_max = std::max( shift_max, shift );
  }
  
  for( int i = 1 ; i < n ; i++ )
    if( vals[i - 1] == vals[i] )
      return false;

  if( shift_max < 0 )
    return true;
  
  return shift_min == shift_max;
}

//----------------------

int replacement( int n, int gondolaSeq[], int replacementSeq[] ) {
  std::vector<int> base( n );
  bool has_base = false;

  std::vector<std::pair<int, int>> repl;

  for( int i = 0 ; i < n ; i++ ){
    int x = gondolaSeq[i];

    if( !has_base && x <= n ){
      has_base = true;
      
      for( int j = 0 ; j < n ; j++ )
        base[(i + j) % n] = (x - 1 + j) % n + 1;
    }

    if( x > n )
      repl.emplace_back( x, i );
  }

  if( !has_base )
    for( int i = 0 ; i < n ; i++ )
      base[i] = i + 1;

  std::sort( repl.begin(), repl.end() );

  int len = 0, last = n;
  for( auto p : repl ){
    // o nu... nu am c++17 in 2014
    int idx = p.second;
    int val = p.first;

    while( base[idx] != val ){
      replacementSeq[len++] = base[idx];
      base[idx] = ++last;
    }
  }

  return len;
}

//----------------------

const int MOD = 1e9 + 9;
using ll = long long;

struct ZP {
  int x;

  ZP( ll x = 0 ): x( x % MOD ) {}
  explicit operator int() { return x; }

  ZP operator *= ( const ZP& that ) { return *this = ZP( x * (ll)that.x ); }
  ZP operator += ( const ZP& that ) {
    x += that.x;
    if( x >= MOD )
      x -= MOD;

    return *this;
  }

  ZP operator * ( const ZP& that ) const { return ZP( *this ) *= that; }
  ZP operator + ( const ZP& that ) const { return ZP( *this ) += that; }
};

ZP lgput( ZP base, int exp ) {
  ZP ret = 1;

  while( exp ){
    if( exp & 1 )
      ret *= base;

    base *= base;
    exp >>= 1;
  }

  return ret;
}

int countReplacement( int n, int inputSeq[] ) {
  if( !valid( n, inputSeq ) )
    return 0;
  
  std::vector<int> base( n );
  bool has_base = false;

  std::vector<std::pair<int, int>> repl;

  for( int i = 0 ; i < n ; i++ ){
    int x = inputSeq[i];

    if( !has_base && x <= n ){
      has_base = true;
      
      for( int j = 0 ; j < n ; j++ )
        base[(i + j) % n] = (x - 1 + j) % n + 1;
    }

    if( x > n )
      repl.emplace_back( x, i );
  }

  std::sort( repl.begin(), repl.end() );

  ZP ret = 1;
  int variante = (int)repl.size();
  int prev = n;
    
  for( auto p : repl ){
    int val = p.first;
    int idx = p.second;

    //printf( "askhdbsahkdas, variante = %d\n", variante );
    
    ret *= lgput( ZP( variante ), val - prev - 1 );
    variante--;
    prev = val;
  }

  // mai avem inca n variante la alegerea primului element din vectorul final (shiftul)
  if( !has_base )
    ret *= ZP( n );
  
  return int(ret);
}

Compilation message (stderr)

gondola.cpp: In function 'int countReplacement(int, int*)':
gondola.cpp:149:9: warning: unused variable 'idx' [-Wunused-variable]
  149 |     int idx = p.second;
      |         ^~~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 10 / 10
• Subtask 4: 5 / 5
• Subtask 5: 10 / 10
• Subtask 6: 20 / 20
• Subtask 7: 5 / 5
• Subtask 8: 15 / 15
• Subtask 9: 15 / 15
• Subtask 10: 10 / 10