# Longest Common Substring

suggest changeGiven 2 string str1 and str2 we have to find the length of the longest common substring between them.

**Examples**

Input : X = “abcdxyz”, y = “xyzabcd” Output : 4

The longest common substring is “abcd” and is of length 4.

Input : X = “zxabcdezy”, y = “yzabcdezx” Output : 6

The longest common substring is “abcdez” and is of length 6.

**Implementation in Java**

```
public int getLongestCommonSubstring(String str1,String str2){
int arr[][] = new int[str2.length()+1][str1.length()+1];
int max = Integer.MIN_VALUE;
for(int i=1;i<=str2.length();i++){
for(int j=1;j<=str1.length();j++){
if(str1.charAt(j-1) == str2.charAt(i-1)){
arr[i][j] = arr[i-1][j-1]+1;
if(arr[i][j]>max)
max = arr[i][j];
}
else
arr[i][j] = 0;
}
}
return max;
}
```

**Time Complexity**

O(m*n)

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