Sort distinct integers in the range [0..N-1]

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下面的程序通过位类标记一个整数是否被输入，然后将所有输入的整数按顺序输出。

/* Copyright (C) 1999 Lucent Technologies *//* From 'Programming Pearls' by Jon Bentley *//* bitsort.c -- bitmap sort from Column 1 * Sort distinct integers in the range [0..N-1] */#include <stdio.h>#define BITSPERWORD 32#define SHIFT 5#define MASK 0x1F#define N 10000000int a[1 + N/BITSPERWORD];void set(int i) { a[i>>SHIFT] |= (1<<(i & MASK)); }void clr(int i) { a[i>>SHIFT] &= ~(1<<(i & MASK)); }int test(int i){ return a[i>>SHIFT] & (1<<(i & MASK)); }int main(){ int i; for (i = 0; i < N; i++) clr(i);/* Replace above 2 lines with below 3 for word-parallel init int top = 1 + N/BITSPERWORD; for (i = 0; i < top; i++) a[i] = 0; */ while (scanf("%d", &i) != EOF) set(i); for (i = 0; i < N; i++) if (test(i)) printf("%d/n", i); return 0;}

在论坛看到的

http://topic.csdn.net/u/20100106/22/956c60f1-8b1b-474d-b19b-29082a8c33f2.html