From 29309c2aebaa900c88546da49a17b2c5aaa61a7a Mon Sep 17 00:00:00 2001
From: xusun000 <2235861811@qq.com>
Date: Wed, 1 Dec 2021 15:44:06 +0800
Subject: [PATCH] add 2012

---
 code_doublelink_2012.cpp | 63 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 code_doublelink_2012.cpp

diff --git a/code_doublelink_2012.cpp b/code_doublelink_2012.cpp
new file mode 100644
index 0000000..1ef31fe
--- /dev/null
+++ b/code_doublelink_2012.cpp
@@ -0,0 +1,63 @@
+#include<stdio.h>
+#include<stdlib.h>
+
+typedef struct node {
+    char data;
+    struct node* link;
+}NODE;
+
+void create(NODE* p, char a[], int pos, int length) {
+    if (pos < length) {
+        p->data = a[pos];
+        p->link = (NODE*)malloc(sizeof(NODE));
+        p->link->data = '\0';//用\0作为结束标志
+        create(p->link, a, pos + 1, length);
+    }
+}
+
+NODE* getSameNode(NODE* a, NODE* b) {
+    int a_length = 0, b_length = 0;
+    NODE* a_p = a->link, * b_p = b->link;
+    while (a_p->data != '\0') {//统计a的节点数
+        a_length++;
+        a_p = a_p->link;
+    }
+    while (b_p->data != '\0') {//统计b的节点数
+        b_length++;
+        b_p = b_p->link;
+    }
+    NODE* a_scan = a->link, * b_scan = b->link;
+    while (a_length < b_length) {//快指针先走
+        b_scan = b_scan->link;
+        b_length--;
+    }
+    while (b_length < a_length) {//快指针先走
+        a_scan = a_scan->link;
+        a_length--;
+    }
+    while (a_length-- > 0) {
+        if (a_scan == b_scan) {
+            return a_scan;
+        }
+        else {
+            a_scan = a_scan->link;
+            b_scan = b_scan->link;
+        }
+    }
+    return NULL;
+}
+
+int main() {
+    NODE a, b;
+    create(&a, "loading", 0, 7);
+    create(&b, "being", 0, 5);
+    NODE* tmp = b.link->link->link;
+    b.link->link = a.link->link->link->link;
+    free(tmp);
+    //两条交叉链构建完毕
+    NODE a_with_head, b_with_head;
+    a_with_head.link = &a;
+    b_with_head.link = &b;
+    NODE* same = getSameNode(&a_with_head, &b_with_head);
+    return 0;
+}
\ No newline at end of file