这是通过的代码:

#include <bits/stdc++.h>
using namespace std;

map<char, int> m1 = {
    {'0',0},
    {'1',1},
    {'2',2},
    {'3',3},
    {'4',4},
    {'5',5},
    {'6',6},
    {'7',7},
    {'8',8},
    {'9',9},
    {'A',10},
    {'B',11},
    {'C',12},
    {'D',13},
    {'E',14},
    {'F',15},
};

map<int, char> m2 = {
    {0,'0'},
    {1,'1'},
    {2,'2'},
    {3,'3'},
    {4,'4'},
    {5,'5'},
    {6,'6'},
    {7,'7'},
    {8,'8'},
    {9,'9'},
    {10,'A'},
    {11,'B'},
    {12,'C'},
    {13,'D'},
    {14,'E'},
    {15,'F'},
};


int main() {
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int jz_1, jz_2;
    string num_str;
    cin >> jz_1 >> num_str >> jz_2;
    int num = 0;
    ...(以下省略)
    return 0;
}

但是如果把头文件换成:

#include <iostream>
#include <string.h>
#include <map>

就会编译失败...

求大佬解惑