Cod sursa(job #2674651)

Utilizator Teodor94Teodor Plop Teodor94 Data 19 noiembrie 2020 19:22:04
Problema Sortare prin comparare Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.39 kb
// Radix sort with base 4

#include <stdio.h>
#include <vector>
using namespace std;

void swap(int& a, int& b) {
  int aux = a;
  a = b;
  b = aux;
}

inline bool isDigit(char c) {
  return c >= '0' && c <= '9';
}

// citire numar natural
int readInt(FILE* fin) {
  char ch;
  int res = 0;

  // eliminam caracterele de dinaintea numarului (spatiu, rand nou, orice caracter care nu este cifra)
  while (!isDigit(ch = fgetc(fin)));

  // adaugam cifrele la numar pana cand caracterul citit nu mai este cifra
  do {
    res = 10 * res + ch - '0';
  } while (isDigit(ch = fgetc(fin)));

  return res;
}

#define MAX_N 500000
#define BASE 4

int v[MAX_N];
vector<int> bucket[BASE];

void sort(int v[], int n, int bitNumber) {
  if (bitNumber == 16)
    return;

  int i, b;
  unsigned int j;
  for (i = 0; i < n; ++i)
    bucket[v[i] >> (bitNumber << 1) & 3].push_back(v[i]);

  i = 0;
  for (b = 0; b < BASE; ++b) {
    for (j = 0; j < bucket[b].size(); ++j)
      v[i++] = bucket[b][j];
    bucket[b].clear();
  }

  sort(v, n, bitNumber + 1);
}

int main() {
  FILE* fin = fopen("algsort.in", "r");
  int n, i;
  fscanf(fin, "%d", &n);
  for (i = 0; i < n; ++i)
    v[i] = readInt(fin);
  fclose(fin);

  sort(v, n, 0);

  FILE* fout = fopen("algsort.out", "w");
  for (i = 0; i < n; ++i)
    fprintf(fout, "%d ", v[i]);
  fclose(fout);
  return 0;
}