题解 | #公共子串计算#

#include <iostream>
#include <string>
using namespace std;

//公共子串计算
class ComSubstrCalc {
  private:
    string s1, s2;

  private:
    //两个字符串较短者的长度（公共子串最大可能长度）
    const int lengthOfTheShorter(void)const;

  public:
    //构造函数
    ComSubstrCalc(const string s1, const string s2);

    //析构函数
    ~ComSubstrCalc();

    //最大公共子串的长度
    const int LenOfMaxComSubstr(void)const;
};

ComSubstrCalc::ComSubstrCalc(const string s1, const string s2) {
    this->s1 = s1;
    this->s2 = s2;
    return;
}

ComSubstrCalc::~ComSubstrCalc() {
}

const int ComSubstrCalc::lengthOfTheShorter(void) const {
    int a = this->s1.size();
    int b = this->s2.size();
    return a < b ? a : b;
}

const int ComSubstrCalc::LenOfMaxComSubstr(void) const {
    int len = this->lengthOfTheShorter();
  
    //从最大可能长度开始，找到公共子串即返回
    for (; len > 0; len--)
        for (int i = 0; i <= this->s1.size() - len; i++) {
            string s = this->s1.substr(i, len);
            for (int j = 0; j <= this->s2.size() - len; j++)
                if (s == this->s2.substr(j, len))
                    return len;
        }
    return 0;
}

int main() {
    string a, b;
    while (cin >> a >> b) { // 注意 while 处理多个 case
        cout << ComSubstrCalc(a, b).LenOfMaxComSubstr() << endl;
    }
}
// 64 位输出请用 printf("%lld")