Chapter 1 of Programming

Question:A file that contains up to n positive integers, each of which is smallerN, WhereN = 10 ^ 7,All positive integers are unique. HowNIntegers are listed in ascending order.

Constraints:Maximum1 MBMemory space is available, with sufficient disk storage space.

 

Exercise 2 Exercise 3 implement bitvectors for sorting.

#include<stdio.h>#define N 10000000#define Shift 5#define BitPerWord (sizeof(int)*8)#define Mask ((1<<Shift)-1)int a[1+N/BitPerWord];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(){    freopen("data.in","r",stdin);    freopen("data.out","w",stdout);    for(int i=0;i<N;i++)        clr(i);    int a;    while(scanf("%d",&a)!=EOF)        set(a);    for(int i=0;i<N;i++){        if(test(i))            printf("%d ",i);    }    printf("\n");    return 0;}

 

Exercise 4: Return K random integers in the ascending order between 0 and n-1.

for i = [0,n)    x[i]=ifor i = [0,k)    swap(i,rand(i,n-1))    print(x[i])

 

Chapter 1 of Programming