add 2019

code_cross_2019.cpp

@@ -0,0 +1,67 @@
+#include<stdio.h>
+#include<stdlib.h>
+
+typedef struct node {
+    int data;
+    struct node* next;
+} NODE;
+
+//通过数组创建链表
+void create(node* n, int length, int pos, int data[]) {
+    if (pos < length) {
+        n->data = data[pos];//赋给struct中的data
+        node* next = (node*)malloc(sizeof(node));//动态分配下一个节点地址
+        n->next = next;//对下一个节点采用递归构建
+        create(n->next, length, pos + 1, data);//递归，pos位置+1
+    }
+    else {
+        n->data = -1;//最后一个节点使用-1作为标识
+    }
+}
+
+void cross_sort(node* n, int length) {
+    //对后半部分就地逆置
+    node* mid = n;
+    node* start = n;
+    int i;
+    for (i = 0;i < length / 2;i++)mid = mid->next;//找到中间节点
+    //从中间开始逆置链表
+    node* s, * t;
+    s = mid->next;
+    mid->next = NULL;
+    while (s->data != -1) {
+        //将s节点摘下来
+        t = s;
+        s = s->next;
+        //将摘下来的节点头插到mid节点之后
+        t->next = mid->next;
+        mid->next = t;
+    }
+    node* tmp = mid;
+    mid = mid->next;//后移
+    tmp->next = NULL;
+    i++;
+    while (i++ < length && mid != NULL) {
+        node* p, * q;
+        //使用p、q暂存start和mid节点
+        p = start->next;
+        q = mid->next;
+        //将mid指针所指节点单独摘下来，注意：要将尾巴(next)甩掉，不然结果不对
+        mid->next = NULL;
+        //插到start节点后面
+        start->next = mid;
+        mid->next = p;
+        //同时移动start和end指针
+        start = p;
+        mid = q;
+    }
+    mid = NULL;
+}
+
+int main() {
+    node* a = (node*)malloc(sizeof(node));
+    int d[] = { 1,2,3,4,5,6,7,8 };
+    create(a, 8, 0, d);
+    cross_sort(a, 8);
+    return 0;
+}