Zeiger Problem beim Implementieren der Suffix-Struktur in C++

Question

Ich habe versucht, Suffix-Struktur mit C++ zu implementieren, indem Sie einige Beispiele online betrachten. Ich stoße auf das Zeigerproblem und kann das Problem nicht beheben. Jede Hilfe wird sehr geschätzt.

/* 
* Implement suffix array to print the maximum suffix substring in a string 
* Algorithm: 
* Build a suffix tree and find the lowest node with multiple children 
* 
*/ 
#include <iostream> 
#include <vector> 
#include <string> 
#include <algorithm> 
#include <ctype.h> 

using namespace std; 

struct node{ 
    char ch; 
    node* next[26]; 
    int treeHeight; 
    int childCount; 
    int end = 0; 
}; 

void insertSuffixIntoTree(node*& root, string suffix){ 
    if (suffix.size() == 0){ 
     return; 
    } 
    char c = suffix[0]; 
    int index = tolower(c) - 'a'; 
    if (root->next[index] == NULL){ 
    root->next[index] = new node(); 
    for (int k = 0; k < 26; k++){ 
     root->next[index]->next[k] = NULL; 
    } 
    root->next[index]->ch = tolower(c); 
    if (suffix.size() == 1){ 
     root->next[index]->end = 1; 
    } 
    } 
    suffix.erase(suffix.begin()); 
    insertSuffixIntoTree(root->next[index], suffix); 
} 

void buildSuffixTree(node* root, string str){ 
    if (root == NULL) cout << "CRAP" << endl; 
    for (int i = str.size() - 1; i >= 0; i--){ 
     string suffix = str.substr(i); 
     cout << "suffix is " << suffix << endl; 
     insertSuffixIntoTree(root, suffix); 
    } 
} 


void printSuffixTree(node* root, string str){ 
    if (root->end){ 
     cout << str << endl; 
     return; 
    } 
    for (int i = 0; i<26; i++){ 
     while (root->next[i]){ 
      str += root->ch; 
      return printSuffixTree(root->next[i],str); 
     } 
    } 
} 

int main() { 
    string str; 
    node* suffixRoot = new node(); 
    suffixRoot->ch = ' '; 
    for (int i = 0; i < 26; i++){ 
     suffixRoot->next[i] = NULL; 
    } 
    cout << "enter the string" << endl; 
    cin >> str; 
    buildSuffixTree(suffixRoot, str); 
    //string result = findMaxSuffix(suffixRoot,str); 
    //cout<<"result is "<<result<<endl; 
    string result = ""; 
    printSuffixTree(suffixRoot,result); 
    getchar(); 
    return 0; 
} 

Der Fehler geschieht bei insertIntoSuffixTree Methode innerhalb buildSuffixTree Methode. Mein Verständnis ist, dass ich meine Zeigeradresse verliere, mit der ich anfing. Irgendeine Idee, wie Sie dieses Problem umgehen können?

Answer 1

Entschuldigung für etwaige Unannehmlichkeiten. Ich habe den Code wie folgt behoben:

/* 
* Implement suffix array to print the maximum suffix substring in a string 
* Algorithm: 
* Build a suffix tree and find the lowest node with multiple children 
* 
*/ 
#include <iostream> 
#include <vector> 
#include <string> 
#include <algorithm> 
#include <ctype.h> 

using namespace std; 

struct node{ 
    char ch; 
    node* next[26]; 
    int treeHeight; 
    int childCount; 
    int end = 0; 
}; 

void insertSuffixIntoTree(node* root, string suffix){ 
    if (suffix.size() == 0){ 
     return; 
    } 
    char c = suffix[0]; 
    int index = tolower(c) - 'a'; 
    if (root->next[index] == NULL){ 
    root->next[index] = new node(); 
    for (int k = 0; k < 26; k++){ 
     root->next[index]->next[k] = NULL; 
    } 
    root->next[index]->ch = tolower(c); 
    if (suffix.size() == 1){ 
     root->next[index]->end = 1; 
    } 
    } 
    suffix.erase(suffix.begin()); 
    insertSuffixIntoTree(root->next[index], suffix); 
} 

void buildSuffixTree(node* root, string str){ 
    if (root == NULL) cout << "CRAP" << endl; 
    for (int i = str.size() - 1; i >= 0; i--){ 
     string suffix = str.substr(i); 
     cout << "suffix is " << suffix << endl; 
     insertSuffixIntoTree(root, suffix); 
    } 
} 

bool checkEmptyVector(node * leaf){ 
    for (int i = 0; i < 26; i++){ 
     if (leaf->next[i] != NULL){ 
      return false; 
     } 
    } 
    return true; 
} 

void printSuffixTree(node* root, string str){ 
    if (root->end){ 
     cout << str << endl; 
    } 
    if (checkEmptyVector(root)){ 
     return; 
    } 
    for (int i = 0; i<26; i++){ 
     //cout << "inside for loop, i is " << i << endl; 
     while (root->next[i]){ 

      str += root->next[i]->ch; 
      printSuffixTree(root->next[i],str); 
      break; 
     } 
    } 
} 

int main() { 
    string str; 
    node* suffixRoot = new node(); 
    suffixRoot->ch = ' '; 
    for (int i = 0; i < 26; i++){ 
     suffixRoot->next[i] = NULL; 
    } 
    cout << "enter the string" << endl; 
    cin >> str; 
    buildSuffixTree(suffixRoot, str); 
    //string result = findMaxSuffix(suffixRoot,str); 
    //cout<<"result is "<<result<<endl; 
    string result = ""; 
    printSuffixTree(suffixRoot,result); 
    getchar(); 
    return 0; 
}