Full array in STL (2)

Topic H: Good at arranging Xiao Ming time limit: Sec Memory limit: MB
submitted: 17 Resolution:
Submitted State Forum Title Description

Xiaoming is very clever, and he is very good at arranging calculations. For example, give Xiaoming a number 5, he can immediately give 1-5 by the dictionary order of the full array, if you want to embarrass him, in the 5 numbers to choose a few numbers to keep him in the whole line, then you are wrong, he is also very good. Now you need to write a program to verify that Bob is good at arranging.

Input

the first line of input integer N (1<n<10) represents how many sets of test data
Each group of test data first row two integers n m (1<n<9,0<m<=n)

Output

Select M characters in 1-n to be fully arranged, all output by dictionary order, one row for each arrangement, and no demarcation between each set of data. As examples

Sample input3 offSample output123121314212324313234414243123132213231312321TipsSTL (The data is a bit large, do not care about the time limit) on the processing of characters. #include <iostream> #include <algorithm> #include <string> using namespace std; int main() {      int i,j,k,T;      cin>>T;      while (T--)      {          int x,y;          string s1,s2;          cin>>x>>y;          for (i=1; i<=x; i++)          {              s1+= ‘0‘ +i;//将字符的每一位赋初值          }          s2=s1.substr(0,y);//截取字符s1，从0to the position of Y and copy to S2;          cout<<s2<<endl;          next_permutation(s1.begin(),s1.end());//对s1进行全排列，从开头到接尾。s1.begin()开始s1.end()结尾。          do          {              if (s2!=s1.substr(0,y))//判断是否截取和排列后的前y是否一样。              {                  s2=s1.substr(0,y);                  cout<<s2<<endl;              }          } while (next_permutation(s1.begin(),s1.end()));//对s1进行全排列，从开头到接尾。s1.begin()开始s1.end()结尾。      }      return 0; }

Full array in STL (2)