add 2009

code_lastK_2009.cpp

@@ -0,0 +1,34 @@
+#include<stdio.h>
+#include<stdlib.h>
+
+typedef struct node {
+    int data;
+    struct node* link;
+}NODE;
+
+void create(NODE* p, int a[], int pos, int length) {
+    if (pos < length) {
+        p->data = a[pos];
+        p->link = (NODE*)malloc(sizeof(NODE));
+        p->link->data = NULL;//用0作为结束标志
+        create(p->link, a, pos + 1, length);
+    }
+}
+
+int getLastK(NODE* p, int k) {
+    NODE* p_fast = p, * p_slow = p;
+    while (--k && p_fast->link != NULL)p_fast = p_fast->link;
+    p_fast = p_fast->link;
+    while (p_fast->data) {
+        p_slow = p_slow->link;
+        p_fast = p_fast->link;
+    }
+    return p_slow->data;
+}
+
+int main() {
+    NODE p;
+    create(&p, (int[]) { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }, 0, 10);
+    int ret = getLastK(&p, 7);
+    return 0;
+}