最长公共子序列(LCS)

/*
 * @author  Panoss
 */
#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<vector>
#include<ctime>
#include<stack>
#include<queue>
#include<list>
using namespace std;
#define DBG 1
#define fori(i,a,b) for(int i = (a); i < (b); i++)
#define forie(i,a,b) for(int i = (a); i <= (b); i++)
#define ford(i,a,b) for(int i = (a); i > (b); i--)
#define forde(i,a,b) for(int i = (a); i >= (b); i--)
#define forls(i,a,b,n) for(int i = (a); i != (b); i = n[i])
#define mset(a,v) memset(a, v, sizeof(a))
#define mcpy(a,b) memcpy(a, b, sizeof(a))
#define dout  DBG && cerr << __LINE__ << " >>| "
#define checkv(x) dout << #x"=" << (x) << " | "<<endl
#define checka(array,a,b) if(DBG) { \
    dout<<#array"[] | " << endl;     forie(i,a,b) cerr <<"["<<i<<"]="<<array[i]<<" |"<<((i-(a)+1)%5?" ":"\n");     if(((b)-(a)+1)%5) cerr<<endl; }
#define redata(T, x) T x; cin >> x
#define MIN_LD -2147483648
#define MAX_LD  2147483647
#define MIN_LLD -9223372036854775808
#define MAX_LLD  9223372036854775807
#define MAX_INF 18446744073709551615
inline int  reint() { int d; scanf("%d",&d); return d; }
inline long relong() { long l; scanf("%ld",&l); return l; }
inline char rechar() { scanf(" "); return getchar(); }
inline double redouble() { double d; scanf("%lf", &d); return d; }
inline string restring() { string s; cin>>s; return s; }

int c[205][205];
/*
c[i][j]表示从A1...i和B1...j的最长公共子序列长度为c[i][j]
状态转移方程为

c[i][j] = 0 i=0或j=0;
c[i][j] = c[i-1][j-1] + 1 Ai = Bj
c[i][j] = max(c[i-1][j],c[i][j-1]) i,j>0,Ai!=Bi
*/
char A[205], B[205];
int A_length, B_length;

void DP()
{
    mset(c,0);
    A_length = strlen(A);
    B_length = strlen(B);
    forde(i,A_length,1)  //先全部后移一位
        A[i] = A[i-1];
    forde(i,B_length,1)
        B[i] = B[i-1];

    forie(i,1,A_length)
    {
        forie(j,1,B_length)
        {
            if(A[i] == B[j])
            {
                c[i][j] = c[i-1][j-1] + 1;
            }
            else
            {
                c[i][j] = max(c[i-1][j],c[i][j-1]);
            }
        }
    }
}

int main()
{
    //freopen("data.txt","r",stdin);
    scanf("%s",A);
    scanf("%s",B);
    DP();
    cout << c[A_length][B_length] << endl;
    return 0;
}