package com.interview.books.leetcodeoj;
import java.util.ArrayList;
import java.util.List;
/**
* Created_By: stefanie
* Date: 14-12-23
* Time: 下午5:39
*/
public class LOJ77_Combination {
List<List<Integer>> sols;
public List<List<Integer>> combine(int n, int k) {
sols = new ArrayList<>();
List<Integer> cur = new ArrayList();
combine(n, 1, cur, k);
return sols;
}
private void combine(int n, int offset, List<Integer> cur, int k){
if(offset > n) return;
cur.add(offset);
if(cur.size() == k){
sols.add(new ArrayList(cur));
} else {
combine(n, offset + 1, cur, k);
}
cur.remove(cur.size() - 1);
combine(n, offset + 1, cur, k);
}
}