剑指offer圆圈中最后剩下的数字 和 迭代器总结

//超时牛客不能通过
class Solution {
public:
    int LastRemaining_Solution(int n, int m){
        if(n == 1){
            return 0;
        }
        if(n == 0){
            return -1;
        }
        list<int> num;
        for(int i = 0;i < n;++i){//存储节点
            num.push_back(i);
        }
        list<int>::iterator iter = num.begin();
        while(num.size() > 1){
            for(int i = 1;i < m;++i){//找到指定节点
                ++iter;
                if(iter == num.end()){
                    iter = num.begin();
                }
            }
            ++iter;
            list<int>::iterator next = iter;//保存下一节点
            if(next == num.end()){
                next = num.begin();
            }
            num.erase(--iter);//删除找到的节点
            iter = next;                       
        }
        return *iter;
    }
};

class Solution {
public:
    int LastRemaining_Solution(int n, int m){
        if(n < 1 ||m < 1){
            return -1;
        }
        
        int last = 0;
        for(int i = 1;i <= n;++i){
            last = (last + m) % i;
        }
        return last;
    }
};