C++ :

#include <bits/stdc++.h>
using namespace std;
vector<int> v;
int main(){
	int n,m,i; 
	cin>>n>>m;
	for(i = 1;i <= n;i++){
		v.push_back(i);
	}
	
	int c = -1;
	while(v.size() != 1){
		//要删第m个数 
		c = (c + m) % v.size();
//		cout<<c<<" "<<v[c]<<endl;
		v.erase(v.begin() + c);
		c--;
	}
	
	cout<<v[0]<<endl;
}

Java :

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int i,j,len;
		List<Integer> list = new ArrayList<Integer>();
		//初始队列
		for(i=1;i<=n;i++) {
			list.add(i);
		}
		int c = -1;//c要删除的下标
		while(list.size() != 1){
	        //要删第m个数 
	        c = (c + m) % list.size();
	        list.remove(c);
	        c--;
	    }
		System.out.println(list.get(0));
		sc.close();	
	}
}