求一个字符串中连续出现次数最多的子串

C++

使用hash map存储每个子串出现的次数

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

pair<int, string> fun(const string& str) {
    int len = str.length();
    if (len == 0){
        return make_pair(0,string(""));
    }
    unordered_map<string, int> map(len*len);

    pair<int, string> ret = make_pair(1, str.substr(0,1));

    for (int i = 0; i < len; ++i) {
        for (int j = 1; j < len - i + 1; ++j) {
            string substr = str.substr(i,j);
            if (map.find(substr) == map.end()) {
                map[substr] = 1;
            } else {
                map[substr] += 1;
                if (map[substr] > ret.first) {
                    ret = make_pair(map[substr], substr);
                } else if (map[substr] == ret.first && substr.length() > ret.second.length()) {
                    ret = make_pair(map[substr], substr);
                }
            }
        }
    }
    return ret;
};
int main()
{
    string str = "zhanghaeha";
    pair<int, string> rs = fun(str);
    cout<<rs.second<<":"<<rs.first<<endl;
    return 0;
}