double free or corruption（out）：0x0000000001a880a0 ***使用向量的組合算法***

Question

我正在編程一個算法，通過計算每個頂點組合的最小樹來計算給定圖上的Steiner樹，但是我的組合算法似乎沒有管理內存使用權，但我看不到我無法做到這一點......

它的工作原理如下，算法接收一個向量，其頂點必須始終包含在圖形，所以首先要創建一個帶有可選頂點的矢量，我們將結合這個頂點（我用10來測試porpouse），然後它計算從1個元素到k個元素的組合（k小於總大小可選頂點集合）。

我們將生成索引的組合（由於它更容易以這種方式分解直接元素），然後將這些元素包含在vComb向量中的這些索引中。

#include <iostream> 
#include <vector> 
using namespace std; 

//Function that calculates the next combination 
bool next_comb(vector<int>& indComb, const int k, const int n) { 
    int i = k - 1; 
    indComb[i]++; 
    while((i >= 0) && (indComb[i] >= n-k+1+i)){ 
     i--; 
     indComb[i]++; 
    } 
    if (indComb[0] > n - k) //We've arrived to the combination (n-k, n-k+1, ..., n) 
     return false; //We can't generate more combinations 
    //Combination is in form(..., x, n, n, n, ..., n). 
    //We will put it in form (..., x, x + 1, x + 2, ...) 
    for (i = i + 1; i < k; ++i) 
     indComb[i] = indComb[i - 1] + 1; 
    return true; 
} 

//Checks if element is in vector 
bool is_in(const int n,const vector<int> v){ 
    for(int i=0; i<v.size(); i++) 
    if(n==v[i]) return true; 
    return false; 
} 

void ST(const vector<int> vMandatory){ 
    cout << "V Mandatory: "; 
    for(int i=0;i<vMandatory.size();i++) 
    cout << vMandatory[i] << " "; 
    cout << " " << endl; 

    //Create and initializate the vector that contains the optional vertices 
    vector<int> vOptional(10-vMandatory.size()); 
    int j=0; 
    for(int i=0;i<10;i++){ 
    if(!is_in(i,vMandatory)){ 
     vOptional[j] = i; 
     j++; 
    } 
    } 

    cout << "V Optional: "; 
    for(int i=0;i<vOptional.size();i++) 
    cout << vOptional[i] << " "; 
    cout << " " << endl; 


    int k = 1; //Initialize number of elements to combine 
    int n = vOptional.size(); //Number of elements inside de set to combine 
    vector<int> indComb; //Vector that will keep the combined indexes of the combination 
    vector<int> vComb; //Vector that will keep the combined elements 
    //We control that the number of elements in the combination can't exceed the number of elements in the set 
    while(k <= vOptional.size()){ 
    indComb.resize(k); 
    vComb.resize(k); 

    //Preparare the first combination 
    for(int i=0;i<k;i++){ 
     indComb[i] = i; 
     vComb[i] = vOptional[indComb[i]]; 
    } 

    cout << "V Primera Combinación: "; 
    for(int i=0;i<vComb.size();i++) 
     cout << vComb[i] << " "; 
    cout << " " << endl; 

    //We make the rest of combinations 
    while(next_comb(indComb,k,n)){ 
     for(int i=0;i<k;i++) 
     vComb[i] = vOptional[indComb[i]]; 

     cout << "V Next Combinations: "; 
     for(int i=0;i<vComb.size();i++) 
     cout << vComb[i] << " "; 
     cout << " " << endl; 
    } 
    k++; 
    cout << k << endl; 
    } 
} 

int main(){ 
    vector<int> vObligatorios(3); 
    vObligatorios[0] = 0; 
    vObligatorios[1] = 1; 
    vObligatorios[2] = 2; 
    ST(vObligatorios); 
} 

這是錯誤的編譯器給我

*** Error in `./a.out': double free or corruption (out): 0x0000000001a880a0 *** 
======= Backtrace: ========= 
/lib/x86_64-linux-gnu/libc.so.6(+0x777e5)[0x7f8f9a4c67e5] 
/lib/x86_64-linux-gnu/libc.so.6(+0x7fe0a)[0x7f8f9a4cee0a] 
/lib/x86_64-linux-gnu/libc.so.6(cfree+0x4c)[0x7f8f9a4d298c] 
./a.out[0x402612] 
./a.out[0x4022c4] 
./a.out[0x401c98] 
./a.out[0x40213e] 
./a.out[0x401b78] 
./a.out[0x401823] 
./a.out[0x4010b4] 
./a.out[0x40149c] 
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7f8f9a46f830] 
./a.out[0x400bb9] 
======= Memory map: ======== 
00400000-00404000 r-xp 00000000 08:06 14156577       /home/pedro/Desktop/a.out 
00603000-00604000 r--p 00003000 08:06 14156577       /home/pedro/Desktop/a.out 
00604000-00605000 rw-p 00004000 08:06 14156577       /home/pedro/Desktop/a.out 
01a76000-01aa8000 rw-p 00000000 00:00 0         [heap] 
7f8f94000000-7f8f94021000 rw-p 00000000 00:00 0 
7f8f94021000-7f8f98000000 ---p 00000000 00:00 0 
7f8f9a146000-7f8f9a24e000 r-xp 00000000 08:06 2621535     /lib/x86_64-linux-gnu/libm-2.23.so 
7f8f9a24e000-7f8f9a44d000 ---p 00108000 08:06 2621535     /lib/x86_64-linux-gnu/libm-2.23.so 
7f8f9a44d000-7f8f9a44e000 r--p 00107000 08:06 2621535     /lib/x86_64-linux-gnu/libm-2.23.so 
7f8f9a44e000-7f8f9a44f000 rw-p 00108000 08:06 2621535     /lib/x86_64-linux-gnu/libm-2.23.so 
7f8f9a44f000-7f8f9a60e000 r-xp 00000000 08:06 2621530     /lib/x86_64-linux-gnu/libc-2.23.so 
7f8f9a60e000-7f8f9a80e000 ---p 001bf000 08:06 2621530     /lib/x86_64-linux-gnu/libc-2.23.so 
7f8f9a80e000-7f8f9a812000 r--p 001bf000 08:06 2621530     /lib/x86_64-linux-gnu/libc-2.23.so 
7f8f9a812000-7f8f9a814000 rw-p 001c3000 08:06 2621530     /lib/x86_64-linux-gnu/libc-2.23.so 
7f8f9a814000-7f8f9a818000 rw-p 00000000 00:00 0 
7f8f9a818000-7f8f9a82e000 r-xp 00000000 08:06 2625962     /lib/x86_64-linux-gnu/libgcc_s.so.1 
7f8f9a82e000-7f8f9aa2d000 ---p 00016000 08:06 2625962     /lib/x86_64-linux-gnu/libgcc_s.so.1 
7f8f9aa2d000-7f8f9aa2e000 rw-p 00015000 08:06 2625962     /lib/x86_64-linux-gnu/libgcc_s.so.1 
7f8f9aa2e000-7f8f9aba0000 r-xp 00000000 08:06 5244862     /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21 
7f8f9aba0000-7f8f9ada0000 ---p 00172000 08:06 5244862     /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21 
7f8f9ada0000-7f8f9adaa000 r--p 00172000 08:06 5244862     /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21 
7f8f9adaa000-7f8f9adac000 rw-p 0017c000 08:06 5244862     /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21 
7f8f9adac000-7f8f9adb0000 rw-p 00000000 00:00 0 
7f8f9adb0000-7f8f9add6000 r-xp 00000000 08:06 2621445     /lib/x86_64-linux-gnu/ld-2.23.so 
7f8f9afb4000-7f8f9afb9000 rw-p 00000000 00:00 0 
7f8f9afd2000-7f8f9afd5000 rw-p 00000000 00:00 0 
7f8f9afd5000-7f8f9afd6000 r--p 00025000 08:06 2621445     /lib/x86_64-linux-gnu/ld-2.23.so 
7f8f9afd6000-7f8f9afd7000 rw-p 00026000 08:06 2621445     /lib/x86_64-linux-gnu/ld-2.23.so 
7f8f9afd7000-7f8f9afd8000 rw-p 00000000 00:00 0 
7ffd45daf000-7ffd45dd0000 rw-p 00000000 00:00 0       [stack] 
7ffd45de6000-7ffd45de8000 r--p 00000000 00:00 0       [vvar] 
7ffd45de8000-7ffd45dea000 r-xp 00000000 00:00 0       [vdso] 
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0     [vsyscall] 
Aborted (core dumped) 

Answer 1

這裏：

while((i >= 0) && (indComb[i] >= n-k+1+i)){ 
    i--; 
    indComb[i]++; 
} 

你可以做i負，導致下一行是不確定的。
爲該案例添加一些跟蹤驗證它確實發生。

（你很可能會改寫內存管理器的內部數據爲載體的分配的存儲。）