Longest Common Subsequence
Longest Common Subsequence.cpp
#include <iostream>
#include <fstream>
#include <math.h>
#include <string>
#define UP 0
#define LEFT 1
#define MATCH 2
using namespace std;
int mat[100][100];
int c[100][100];
int b[100][100];
std::string x;
std::string y;
void lenlen()
{
//int &ref = cache[]
for(int i = 0; i <= x.length(); i ++)
{
c[i][0] = 0;
}
for(int i = 0; i <= y.length(); i ++)
{
c[0][i] = 0;
}
for(int i = 1; i <= x.length(); i ++)
{
for(int j = 1; j <= y.length(); j ++)
{
if(x[i - 1] == y[j - 1])
{
c[i][j] = c[i - 1][j - 1] + 1;
b[i][j] = MATCH;
}
else if(c[i - 1][j] > c[i][j - 1])
{
c[i][j] = c[i - 1][j];
b[i][j] = UP;
}
else
{
c[i][j] = c[i][j - 1];
b[i][j] = LEFT;
}
}
}
}
void print(int i, int j)
{
if(i == 0 && j == 0)
return;
if(i < 0 || j < 0)
return;
if(b[i][j] == MATCH)
{
print(i - 1, j - 1);
cout << x[i - 1];
}
else if(b[i][j] == UP)
{
print(i - 1, j);
}
else
print(i, j - 1);
}
int main()
{
fstream fin("input.txt");
int n, m;
fin >> n >> m;
fin >> x >> y;
lenlen();
cout << c[n][m] << endl;
print(n, m);
}