USACO-palsquare 遇到的一个坑

 /**
 ID: njuwz151
 TASK: palsquare
 LANG: C++
 */
 #include <iostream>
 #include <cstdio>
 #include <cstring>

 using namespace std; 

 char baseTable[] = {'', '', '', '', '', '', '', '', '', '', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K'};

 char* reverse(const char* src, int len);

 char* base10ToBaseN(int number, int base);

 int main() {
     freopen("palsquare.in", "r", stdin);
     freopen("palsquare.out", "w", stdout);
     int base;
     cin >> base;
     char* palNumber;
     char* palSquare;
     char* reverseSquare;
     for(int i = ; i <= ; i++) {
         if(!palNumber) {
             delete palNumber;
             palNumber = NULL;
         }
         palNumber = base10ToBaseN(i, base);
         if(!palSquare) {
             delete palSquare;
             palSquare = NULL;
         }
         palSquare = base10ToBaseN(i * i, base);
         if(!reverseSquare) {
             delete palSquare;
             palSquare = NULL;
         }
         reverseSquare = reverse(palSquare, strlen(palSquare));
         for(int j = ; j < strlen(palSquare); j++) {
             if(palSquare[j] != reverseSquare[j]) {
                 break;
             }
             if(j == strlen(palSquare) - ) {
                 cout << palNumber << " " << palSquare << endl;
             }
         }
     }
     return ;
 } 

 char* reverse(const char* src, int len) {
     char* result = new char[len+];
     for(int i = ; i < len; i++) {
         result[i] = src[len -  - i];
     }
     result[len] = ;
     return result;
 }

 char* base10ToBaseN(int number, int base) {
     char* result = new char[];
     int len = ;
     while(number != ) {
         result[len] = baseTable[number % base];
         number /= base;
         len++;
     }
     result[len] = ;
     return reverse(result, strlen(result));
 }

这是原来的代码，在本机跑的时候没有问题，但是在评测的时候报错了。错误信息如下：

program:_malloc.c:2392:_sysmalloc:_Assertion_`(old_top_==_initial_top_(av)_&&_old_size_==_0)_||_((unsigned_long)_(old_size)_>=_MINSIZE_&&_prev_inuse_(old_top)_&&_((unsigned_long)_old_end_&_(pagesize_-_1))_==_0)'_failed. -------------------

在查阅资料之后，应该是说我的代码越界使用了内存，于是我重新写了代码。

 /**
 ID: njuwz151
 TASK: palsquare
 LANG: C++
 */
 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <string>

 using namespace std; 

 string baseTable = "0123456789ABCDEFGHIJK";

 string reverse(string src);

 string base10ToBaseN(int number, int base);

 int main() {
     freopen("palsquare.in", "r", stdin);
     freopen("palsquare.out", "w", stdout);
     int base;
     cin >> base;
     for(int i = ; i <= ; i++) {
         string palNumber = base10ToBaseN(i, base);
         string palSquare = base10ToBaseN(i * i, base);
         string reverseSquare = reverse(palSquare);
         for(int j = ; j < palSquare.size(); j++) {
             if(palSquare[j] != reverseSquare[j]) {
                 break;
             }
             if(j == palSquare.size() - ) {
                 cout << palNumber << " " << palSquare << endl;
             }
         }
     }

     return ;
 } 

 string reverse(string src) {
     int len = src.size();
     string result;
     for(int i = len - ; i > -; i--) {
         result += src[i];
     }
     return result;
 }

 string base10ToBaseN(int number, int base) {
     string result;
     while(number > ) {
         result = baseTable[number % base] + result;
         number /= base;
     }
     return result;
 }

使用了string 来替代数组，说起来我也不是专业写C/C++的，之前char数组和string混合使用出错了，就单用char数组解决问题了，但是这次没能用好char数组，说明我对内存管理还是有一定的认知缺乏。