3301 Square words

#include<cstdio>
#include<string>
#include<iostream>
using namespace std;
const int N=1e3+10;
int n,f[N][N];
string s;
int ans=0x7fffffff; 
inline int LCS(string a,string b){
    int l1=a.length(),l2=b.length();
    for(int i=0;i<l1;i++){
        for(int j=0;j<l2;j++){
            if(!i||!j) f[i][j]=a[i]==b[j];
            else{
                if(a[i]==b[j]) f[i][j]=f[i-1][j-1]+1;
                else f[i][j]=max(f[i-1][j],f[i][j-1]);
            }
        }
    }
    return f[l1-1][l2-1];
}
int main(){
    cin>>n>>s;
    for(int i=0;i<n-1;i++){
        string a,b;
        for(int j=0;j<=i;j++) a+=s[j];
        for(int j=i+1;j<n;j++) b+=s[j];
        int anc=LCS(a,b);
        ans=min(ans,n-2*anc);
    }
    printf("%d\n",ans);
    return 0;
}