在循环(C++）中用新指针填充映射

Populating map with new pointers in a loop (C++)

本文关键字：指针 填充 映射 新指针 循环 C++      更新时间：2023-10-16

所以我正在处理leetcode中的带有随机指针的复制列表问题，遇到了一些问题。

for (; iterateOG->next != nullptr; 
iterateOG = iterateOG->next) {
Node* tmp = new Node;
hashTable.insert(std::pair<Node*,Node*>(iterateOG,tmp));
}

因此，我想为原始列表中的每个现有节点创建一个新的Node对象。运行测试用例后，我收到一条错误消息，比如在下面包含HINT

'hashTable' &lt;== Memory access at offset 912 overflows this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext
(longjmp and C++ exceptions *are* supported)

有人知道是什么导致了这个问题吗？我知道原因可能是因为我创建了一个新对象，但没有在范围内对其进行任何处理，但我看不到解决这个问题的方法。如有任何帮助，我们将不胜感激。非常感谢。

完整代码和下方的错误消息

/*
// Definition for a Node.
class Node {
public:
int val;
Node* next;
Node* random;
Node() {}
Node(int _val, Node* _next, Node* _random) {
val = _val;
next = _next;
random = _random;
}
};
*/
class Solution {
public:
Node* copyRandomList(Node* head) {
if (head == nullptr)
return nullptr;
Node* iterateOG = head;
std::map<Node*, Node*> hashTable;
for (; iterateOG->next != nullptr; 
iterateOG = iterateOG->next) {
Node* tmp = new Node;
hashTable.insert(std::pair<Node*,Node*>(iterateOG,tmp));
}
std::cout << endl;
iterateOG = head;
for (; iterateOG->next != nullptr; 
iterateOG = iterateOG->next) {
hashTable.find(iterateOG)->second->val = iterateOG->val;
hashTable.find(iterateOG)->second->next = hashTable.find(iterateOG->next)->second;
hashTable.find(iterateOG)->second->random = hashTable.find(iterateOG->random)->second;
std::cout << hashTable.find(iterateOG)->second->val << ',';
}
std::cout << endl;
return hashTable.find(head)->second;
}
};

错误消息

=================================================================
==29==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffc4dbbbb70 at pc 0x00000041d7eb bp 0x7ffc4dbbb7b0 sp 0x7ffc4dbbb7a8
READ of size 8 at 0x7ffc4dbbbb70 thread T0
#2 0x7fa042ca92e0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202e0)
Address 0x7ffc4dbbbb70 is located in stack of thread T0 at offset 912 in frame
This frame has 14 object(s):
[32, 33) '__c'
[96, 97) '__c'
[160, 168) 'iterateOG'
[224, 232) 'tmp'
[288, 296) '&lt;unknown&gt;'
[352, 360) '&lt;unknown&gt;'
[416, 424) '&lt;unknown&gt;'
[480, 488) '&lt;unknown&gt;'
[544, 552) '&lt;unknown&gt;'
[608, 616) '&lt;unknown&gt;'
[672, 680) '&lt;unknown&gt;'
[736, 744) 'head'
[800, 816) '&lt;unknown&gt;'
[864, 912) 'hashTable' &lt;== Memory access at offset 912 overflows this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext
(longjmp and C++ exceptions *are* supported)
Shadow bytes around the buggy address:
0x100009b6f710: 00 f2 f2 f2 f2 f2 f2 f2 f8 f2 f2 f2 f2 f2 f2 f2
0x100009b6f720: f8 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 f2 f2 f2 f2
0x100009b6f730: 00 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 f2 f2 f2 f2
0x100009b6f740: 00 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 f2 f2 f2 f2
0x100009b6f750: 00 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 f2 f2 f2 f2
=&gt;0x100009b6f760: f8 f8 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00[f2]f2
0x100009b6f770: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
0x100009b6f780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x100009b6f790: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x100009b6f7a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x100009b6f7b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable:           00
Partially addressable: 01 02 03 04 05 06 07 
Heap left redzone:       fa
Freed heap region:       fd
Stack left redzone:      f1
Stack mid redzone:       f2
Stack right redzone:     f3
Stack after return:      f5
Stack use after scope:   f8
Global redzone:          f9
Global init order:       f6
Poisoned by user:        f7
Container overflow:      fc
Array cookie:            ac
Intra object redzone:    bb
ASan internal:           fe
Left alloca redzone:     ca
Right alloca redzone:    cb
==29==ABORTING

错误在这一行：

hashTable.find(iterateOG)->second->next = hashTable.find(iterateOG->next)->second;

对于最后一个节点，iterateOG->next具有不在hashTable中的值。

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