面试题：map递归调用搜索

递归map

#include <bits/stdc++.h>

using namespace std;

class B {
    
public:
    string key;
    map<string, B> nestedMap;
};

map<string, B> mp;

B* findKeyInNestedMap(const string& key, map<string, B>& mp) {
    
    for (auto& item : mp) {
    
        if (item.first == key)  return &(item.second);
        else {
    
            B* result = findKeyInNestedMap(key, item.second.nestedMap);
            if (result != nullptr)
                return result;
        }
    }

    return nullptr; // not found
}

int main() {
    
    string key = "name";

    B* result = findKeyInNestedMap(key, mp);

    if (result != nullptr) cout << result->key << endl;
    else cout << "NOT FIND!" << endl;

    return 0;
}

测试

#include <bits/stdc++.h>

using namespace std;

class B {
    
public:
    string key;
    map<string, B> nestedMap;
};

map<string, B> mp;

B* findKeyInNestedMap(const string& key, map<string, B>& mp) {
    
    for (auto& item : mp) {
    
        if (item.first == key)  return &(item.second);
        else {
    
            B* result = findKeyInNestedMap(key, item.second.nestedMap);
            if (result != nullptr)
                return result;
        }
    }

    return nullptr; // not found
}

int main() {
    
    B b1, b2, b3;
    b1.key = "b1_key";
    b2.key = "b2_key";
    b3.key = "b3_key";

    // 嵌套的 map 中的值也是一个嵌套的 map
    b1.nestedMap["name"].key = "b1_nested_value1";
    b2.nestedMap["b2_nested_key1"].key = "b2_nested_value1";
    b2.nestedMap["b2_nested_key2"].key = "b2_nested_value2";
    b3.nestedMap["b3_nested_key1"].key = "b3_nested_value1";
    b3.nestedMap["b3_nested_key2"].key = "b3_nested_value2";

    mp.insert({
     "b1", b1 });
    mp.insert({
     "b2", b2 });
    mp.insert({
     "b3", b3 });

    string testKey1 = "name";
    B* result1 = findKeyInNestedMap(testKey1, mp);

    if (result1 != nullptr) cout << result1->key << endl;
    else cout << "NOT FIND!" << endl;

    return 0;
}