lexicographic

For permutations, given N and k , I have a function that finds the k th permutation of N in lexicographic order. Also, given a permutation perm , I have a function that finds the lexicographic index of the permutation among all permutations of N . To do this, I used the "factorial decomposition" as suggested in this answer . Now I want to do the same thing for integer partitions of N . For example, for N=7 , I want to be able to back and forth between the index (left) and the partition (right): 0 ( 7 ) 1 ( 6 1 ) 2 ( 5 2 ) 3 ( 5 1 1 ) 4 ( 4 3 ) 5 ( 4 2 1 ) 6 ( 4 1 1 1 ) 7 ( 3 3 1 ) 8 ( 3 2 2 )

I want to sort a large array of integers (say 1 millon elements) lexicographically. Example: input [] = { 100, 21 , 22 , 99 , 1 , 927 } sorted[] = { 1 , 100, 21 , 22 , 927, 99 } I have done it using the simplest possible method: convert all numbers to strings (very costly because it will take huge memory) use std:sort with strcmp as comparison function convert back the strings to integers Is there a better method than this? Use std::sort() with a suitable comparison function. This cuts down on the memory requirements. The comparison function can use n % 10 , n / 10 % 10 , n / 100 % 10 etc. to

Finding the Lexicographically minimal string rotation is a well known problem, for which a linear time algorithm was proposed by Jean Pierre Duval in 1983. This blog post is probably the only publicly available resource that talks about the algorithm in detail. However, Duval's algorithms is based on the idea of pairwise comparisons ("duels"), and the blog conveniently uses an even-length string as an example. How does the algorithm work for odd-length strings, where the last character wouldn't have a competing one to duel with? One character can get a " bye ", where it wins without

I tried to create the code to generate all possible combination of the given string in the lexicographical order: The code that I wrote is: void get(char *n) { int l=strlen(n); sort(n,n+l); int k=0,m,i,j,z; while(k<l) { m=k; for(i=k;i<l;i++) { for(j=k;j<=i;j++) cout<<n[j]; cout<<"\n"; } for(z=m+2;z<l;z++) cout<<n[m]<<n[z]<<"\n"; k++; } } int main() { char n[100]; cin>>n; get(n); return 0; } Suppose the string is : abcde My code is not generating combinations like: abd abe The output I am getting for the string abcde are: a ab abc abcd abcde ac ad ae b bc bcd bcde bd be c cd cde ce d de e My

I have the following operator< that is supposed to sort first by a value, then by another value: inline bool operator < (const obj& a, const obj& b) { if(a.field1< b.field1) return true; else return a.field2 < b.field2; } I have the feeling this is incorrect and that you can't do that without another third comparaison test on the members variables, but I can't find any example where this doesn't work. So whould this really sort as expected? thanks edit : I would have coded it as : inline bool operator < (const obj& a, const obj& b) { if(a.field1< b.field1) return true; else if(a.field1> b

In the package initialization part of the Go specification, what does "lexical file name order" mean? To ensure reproducible initialization behavior, build systems are encouraged to present multiple files belonging to the same package in lexical file name order to a compiler. From Wikipedia : Lexical order is a generalization of the way the alphabetical order of words is based on the alphabetical order of their component letters. In practice this means files names are compared as strings, using the character codes to decide order. Order of character codes of the English alphabet follow the

What is the exact meaning of lexicographical order? How it is different from alphabetical order? Elliott Frisch lexicographical order is alphabetical order. The other type is numerical ordering. Consider the following values, 1, 10, 2 Those values are in lexicographical order. 10 comes after 2 in numerical order, but 10 comes before 2 in "alphabetical" order. 来源： https://stackoverflow.com/questions/45950646/what-is-lexicographical-order