题解 | #查找两个字符串a,b中的最长公共子串#

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

int main(){
    string s1,s2;
    std::cin >> s1 >>  s2;
    if(s1.size()>s2.size()){
        swap(s1, s2);
    }
    int m = s1.size(),n=s2.size();
    int f[m+1][n+1];
    int posx=0,posy=0;
    memset(f,0,sizeof(int)*(m+1)*(n+1));
    for(int i=1;i<=m;i++){
        for(int j=1;j<=n;j++){
            if(s1[i-1]==s2[j-1]){
                if(f[i-1][j-1]){
                    f[i][j]=f[i-1][j-1]+1;
                }else{
                    f[i][j]=1;
                }
            }
            if(f[i][j]>f[posx][posy]){
                posx=i;posy=j;
            }
        }
    }
    string res = s1.substr(posx-f[posx][posy],f[posx][posy]);
    std::cout << res;
    return 0;
}