遇到啥问题啊？

帮你写下吧，题目不难，重在理解
主要理解我代码里的41行，这行理解了基本上就没问题了



完整代码
package day0611;
import java.util.ArrayList;
import java.util.List;
public class Demo1 {
static int count = 0;
public static void main(String[] args) {
//控制台输入过程自己写
int n = 4, m = 2;
System.out.println("输出------");
comb(n,m);
System.out.println("总数："+count);
}
//从1-n中选出m个数
static void comb(int n,int m) {
List<Integer> line = new ArrayList<Integer>();
combnext(line,n,m);
}
//对于每一个行再添加一个
static void combnext(List<Integer> line,int n,int m) {
int sta = 0;
if(line.size() != 0) {//去line中已存在的最大数
sta = line.get(line.size()-1);
}
//最大数与n间的差距，则为都可以添加的值
//比如最大数为2，n为5，那么下一个可添加的数可以是3,4,5
for(int i=sta+1;i<=n;i++) {
line.add(i);//line 增加一个数后
if(line.size() == m) {//已经满足条件
printLine(line);
count++;
}else {//不满足继续添加
//调用自身进行迭代
combnext(line,n,m);
}
//最关键的一步 移除最后添加的一个进行回溯
line.remove(line.size()-1);
}
}
static void printLine(List<Integer> line) {
for(int i:line) {
System.out.print(i+" ");
}
System.out.println("");
}
}

package csq;
import java.util.ArrayList;
import java.util.List;
import java.util.Stack;
public class CombineCount {
public static Stack<Integer> stack = new Stack<Integer>();
public static void main(String[] args) {
//-数字在这里定义-
int n = 4;//
int m = 2;//
start(n, m);//
//----------------
}
public static void start(int n, int m){
List<Integer> list = new ArrayList<Integer>();
for(int i = 1 ; i <= n; i++){
list.add(i);
}
combine(list, m, 0);
}
private static void combine(List<Integer> list, int targ, int cur) {
if(cur == targ) {
System.out.println(stack);
return;
}
for(int i=0;i<list.size();i++) {
if(!stack.contains(list.get(i))) {
if(judgeInc(stack, list.get(i))){
continue;
}
stack.add(list.get(i));
combine(list, targ, cur+1);
stack.pop();
}
}
}
private static boolean judgeInc(Stack<Integer> stack, int incNum) {
if(stack.isEmpty()){
return false;
}else if(stack.get(stack.size()-1) >= incNum){
//System.out.println(stack+" "+stack.get(stack.size()-1));
return true;
}else{
return false;
}
}
}

还要显示几种，忘了，加上去
package csq;
import java.util.ArrayList;
import java.util.List;
import java.util.Stack;
public class CombineCount {
public static Stack<Integer> stack = new Stack<Integer>();
static int allCount = 0;
public static void main(String[] args) {
//-数字在这里定义-
int n = 4;//
int m = 2;//
start(n, m);//
//----------------
System.out.println("共"+allCount+"种");
}
public static void start(int n, int m){
List<Integer> list = new ArrayList<Integer>();
for(int i = 1 ; i <= n; i++){
list.add(i);
}
combine(list, m, 0);
}
private static void combine(List<Integer> list, int targ, int cur) {
if(cur == targ) {
System.out.println(stack);
allCount++;
return;
}
for(int i=0;i<list.size();i++) {
if(!stack.contains(list.get(i))) {
if(judgeInc(stack, list.get(i))){
continue;
}
stack.add(list.get(i));
combine(list, targ, cur+1);
stack.pop();
}
}
}
private static boolean judgeInc(Stack<Integer> stack, int incNum) {
if(stack.isEmpty()){
return false;
}else if(stack.get(stack.size()-1) >= incNum){
//System.out.println(stack+" "+stack.get(stack.size()-1));
return true;
}else{
return false;
}
}
}

求组合c42就c42，搞得这么复杂，害我一下都没读懂题目。

双循环for（var i=0；i小于m；i++）｛
for（var j=0；j小于m-i；j++）｛｝｝