The longest common substring problem

My problem-solving ideas:

Generate a dynamic planning table, which is a matrix DP of size m*n (M and n are two string lengths respectively);

DP[I][J] Process:

1. Matrix The first column is dp[0~m-1][0], for a certain position (i,0), if str1[i]==str2[0], to dp[i][0]=1,. otherwise dp[i][0]=0;

2. The first line of the matrix is dp[0][0~n-1], for a position (0,J), if STR1[0]==STR2[J], to dp[0][j]=1,. otherwise dp[i][0]=0;

3. The rest of the positions are calculated from left to right, top to bottom, and the value of dp[i][j] may only be in two cases:

A. If STR1[I]!=STR2[J], it is impossible to make the last character of the common substring str1[i] and str2[j], so that dp[i][j]=0;

B. If str1[i]==str2[j], description str1[i] and str2[j] can be used as the last character of the common substring, dp[i][j]=dp[i-1][j-1]+1;

After generating the dynamic planning table, the largest number in the table is the length of the common substring

Here is the specific code:

#include <iostream>

#include <string>

using namespace Std;

int dp[8][8] = {0};//the size of the two-dimensional matrix is defined by itself, guaranteeing the ability to tolerate the string.

void Initdp (char *str1, char *str2)

{

int len1 = strlen (STR1);

int len2 = strlen (STR2);

for (int i = 0; i < len1; i++)

{

if (str1[i] = = Str2[0])

{

Dp[i][0] = 1;

}

}

for (int j = 1; j < Len2; J + +)

{

if (str2[j] = = Str1[0])

{

DP[0][J] = 1;

}

}

for (int i = 1; i < len1; i++)

{

for (int j = 1; j < Len2; J + +)

{

if (str1[i] = = Str2[j])

{

DP[I][J] = dp[i-1][j-1] + 1;

}

}

}

}

void Maxchar (char *str1, char *str2)

{

int len1 = strlen (STR1);

int len2 = strlen (STR2);

int max = 0;

int end = 0;

for (int i = 0; i < len1; i++)

{

for (int j = 0; J < Len2; J + +)

{

if (Dp[i][j]>max)

{

max = Dp[i][j];

end = i;

}

}

}

for (int i = end-max+1; I <= end; ++i)

{

printf ("%c", Str1[i]);

}

printf ("\ n");

}

int main ()

{

Char *str1 = "AB123CD";

Char *str2 = "DB1234CG";

INITDP (str1, str2);

Maxchar (str1, str2);

return 0;

}

If there's a better way for a great God, please tell the niche, thank you.

The longest common substring problem