给定一个字符串数组，将所有字符串分组，每一组的字符串包含的字符相同但是顺序不同。

如：

输入: ["eat", "tea", "tan", "ate", "nat", "bat"],

输出:

[

 ["ate","eat","tea"],

 ["nat","tan"],

 ["bat"]

]

#include <algorithm>
#include <fstream>
#include <iostream>
#include <string>
#include <unordered_map>
#include <vector>
#include "mpi.h"

#define ROOT_PROCESS 0

using namespace std;

vector<string> all_content;
unordered_map<string, vector<string>> grouped_strings;
unordered_map<size_t, size_t> length_counts;

void read_all(ifstream& file) {
    string line;

    while (getline(file, line)) {
        if (!line.empty() && line.back() == 13)
            line.pop_back();

        all_content.push_back(line);

        string sorted_line = line;
        sort(sorted_line.begin(), sorted_line.end());

        grouped_strings[sorted_line].push_back(line);
        length_counts[line.size()] += 1;
    }
}

void print() {
    if (grouped_strings.empty()) return;

    cout << "[" << endl;
    for (auto it = grouped_strings.begin(); it != grouped_strings.end(); ++it) {
        cout << " [";
        for (const auto& str : it->second) {
            cout << str << ",";
        }
        cout << "]" << endl;
    }
    cout << "]" << endl;

    for (const auto& pair : length_counts) {
        cout << pair.first << ": " << pair.second << endl;
    }
}

int main(int argc, char* argv[]) {
    MPI_Init(&argc, &argv);

    int num_procs, my_rank;
    MPI_Comm_size(MPI_COMM_WORLD, &num_procs);
    MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);

    if (argc != 2) {
        if (my_rank == ROOT_PROCESS)
            cerr << "Usage: " << argv[0] << " <filename>" << endl;
        MPI_Finalize();
        return 1;
    }

    ifstream file(argv[1]);
    if (!file.is_open()) {
        if (my_rank == ROOT_PROCESS)
            cerr << "Error opening file" << endl;
        MPI_Finalize();
        return 1;
    }

    if (my_rank == ROOT_PROCESS) {
        read_all(file);
        file.close();
    }

    // Broadcast data to all processes
    // Assume all_content, grouped_strings, and length_counts are filled on ROOT_PROCESS
    MPI_Bcast(&all_content[0], all_content.size(), MPI_CHAR, ROOT_PROCESS, MPI_COMM_WORLD);

    // Determine portion of work for each process
    int portion_size = all_content.size() / num_procs;
    int start = my_rank * portion_size;
    int end = (my_rank + 1) * portion_size;

    // Each process works on its portion of data
    for (int i = start; i < end; ++i) {
        string line = all_content[i];
        string sorted_line = line;
        sort(sorted_line.begin(), sorted_line.end());

        grouped_strings[sorted_line].push_back(line);
        length_counts[line.size()] += 1;
    }

    // Gather results to ROOT_PROCESS for printing
    MPI_Barrier(MPI_COMM_WORLD);
    if (my_rank == ROOT_PROCESS) {
        print();
    }

    MPI_Finalize();
    return 0;
}