算法导论15章LCS实现(c++)

#include "stdafx.h"
#include <iostream>
#include <math.h>

using namespace std;

int c[8][7],b[8][7];

void LCS_length (const string& x, const string& y)
{
    int m = x.length();
    int n = y.length();
    for (int i = 0; i <= m; i++)
        c[i][0] = 0;
    for (int j = 1; j <= n; j++)
        c[0][j] = 0;
    for (int i = 1; i <= m; i++)
        for (int j = 1; j <= n; j++)
        {
            if (x[i-1] == y[j-1])//x y 都是从下标 0 开始存储
            {
                c[i][j] = c[i-1][j-1] + 1;
                b[i][j] = 0;
            }
            else if (c[i-1][j] >= c[i][j-1])
            {
                c[i][j] = c[i-1][j];
                b[i][j] = 1;
            }
            else
            {
                c[i][j] = c[i][j-1];
                b[i][j] = -1;
            }
        }
}

void Print_LCS (const string& x, int i, int j)
{
    if (i == 0 || j == 0)
        return;
    if (b[i][j] == 0)
    {
        Print_LCS (x, i-1, j-1);
        cout<<x[i-1];//x 从下标0开始
    }
    else if (b[i][j] == 1)
        Print_LCS (x, i-1, j);
    else
        Print_LCS (x, i, j-1);
}
int main()
{
    string x = "ABCBDAB";
    string y = "BDCABA";
    LCS_length (x, y);
    for (int i = 0; i < 8; i++)
    {
        for (int j = 0; j < 7; j++)
        {
            if(j != 0)
                cout<<" ";
            cout<<c[i][j];
        }
        cout<<endl;
    }
    Print_LCS (x, 7, 6);
    return 0;
}