剑指offer 孩子们的游戏(圆圈中最后剩下的数)

参考别人的代码
方法一：链表模拟

import java.util.LinkedList;
import java.util.List;

public class Solution {
    public int LastRemaining_Solution(int n, int m) {
        if (n<=0 || m<=0) return -1;

        List<Integer> list=new LinkedList<>();
        for (int i=0;i<n;i++) list.add(i);

        int p=0;
        while (list.size()>1){
            p=(p+m-1)%list.size();
            list.remove(p);
        }

        return list.get(0);
    }
}

方法二：数学公式
f(N,M) = ( f(N−1,M) + M ) % N

public class Solution {
    public int LastRemaining_Solution(int n, int m) {
        if (n<=0 || m<=0) return -1;
        if (n==1) return 0;

        return (LastRemaining_Solution(n-1,m)+m)%n;
    }
}

或

public class Solution {
    public int LastRemaining_Solution(int n, int m) {

        if (n<=0 || m<=0) return -1;

        int p=0;
        for (int i=2;i<=n;i++){
            p=(p+m)%i;
        }

        return p;

    }
}