Use C + + to generate 6 random numbers in 1-33, no duplicates

Generates 6 random numbers in 1-33, no duplicates

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Method 1. Each random number is generated to facilitate the comparison of all previous random numbers, and if there are duplicates, do not, re-select.

However, this method is time-consuming and can cause huge problems when the volume of data is huge and there are some limitations.

For example, to generate 10,000 random numbers, with a range of 0-9999 and no repetition, the last few random numbers can take a long time to filter out.

Method 2. Here we think from another angle,

Let's say we've got an array with an array length of 10000, which stores data 0-9999, and I'm now trying to figure out how to make a 10,000-number random arrangement.

Then I get a random number, and if I just want 100 of them, I'll take 100 out of the front. Here, we use a function random_shuffleinside the algorithm.h to do simple processing.

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#include <algorithm>#include <iostream>#include <vector>using namespacestd;voidrandperm(intNum){vector<int> temp;for(inti = 0; i < Num; ++i){temp.push_back(i + 1);}random_shuffle(temp.begin(), temp.end());//for (int i = 0; i < temp.size(); i++)for(inti = 0; i < 6; i++){cout << temp[i] << " ";}}intmain(){randperm(33);return0;}

Method 3. use a linked list (sort in the unique can go to weight) or set

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#include<iostream>usingnamespace std;#include <stdlib.h>#include <time.h>#include <list>#include <set>intact_rand(inta,intb){       int m = rand()%(b-a+1)+a;      cout << "m = "<< m << endl;    returnm;}voidgenRandomList(){  list<int> l;    while( l.size() < 6)    {        intrandnum=act_rand(1,6);        l.push_back(randnum);        l.sort();        l.unique();    }        list<int>::iterator it;//迭代器    for(it = l.begin(); it != l.end(); it++)    {        cout << *it << ‘ ‘;    }}voidgenRandomSet(){  set<int> s;    while( s.size() < 6)    {        intrandnum=act_rand(1,33);        s.insert(randnum);     }         set<int>::iterator it;//迭代器    for(it = s.begin(); it != s.end(); it++)    {        cout << *it << ‘ ‘;    }}

Reference:

C + + generates non-repeating random integers-~ ~ (V_V) ~ ~-CSDN Blog

http://blog.csdn.net/pythontojava/article/details/45132059

Random numbers and non-repeating random numbers in C + +-Pilgrimage Suns-Blog Park

Http://www.cnblogs.com/salan668/p/3652532.html

(1) C + + produces non-repeating random number _ Jin Tingpo _ Sina Blog

Http://blog.sina.com.cn/s/blog_4522f0b8010008r5.html

Use C + + to generate 6 random numbers in 1-33, no duplicates