题解 | #输出单向链表中倒数第k个结点#

#include<iostream>
#include<algorithm>
using namespace std;

const int N = 1005;
int head, e[N], ne[N], idx;

void init () {
    idx = 0, head = -1;
}

void add_to_tail(int x) {
    e[idx] = x;
    ne[idx] = -1;
    if (head == -1) head = idx++;
    else {
        int t = head;
        while (ne[t] != -1) t = ne[t];
        ne[t] = idx++;
    }
}

int main() {
    int n, k;

    while (cin >> n) {

        init();
        while (n--) {
            int x;
            cin >> x;
            add_to_tail(x);
        }
        cin >> k;

        int i = head, j = i;
        while (k--) j = ne[j];

        while (ne[j] != -1) {
            i = ne[i], j = ne[j];
        }
        cout << e[i + 1] << endl;
    }
    return 0;
}

双指针算法，数组模拟链表。