```
package dynamicProgramming
import kotlin.math.max
/* This algorithm is Longest Common Subsequence
* @param s1,s2 - strings to be compared
* @return Length of longest common subsequence between two strings.
Eg., for stage and sale it is 3.(sae is the longest common subsequence)
*/
fun lcs(s1: String, s2: String): Int {
val L = Array(s1.length + 1) { IntArray(s2.length + 1) }
for (i in 0..s1.length) {
for (j in 0..s2.length) {
if (i == 0 || j == 0) L[i][j] = 0
else if (s1[i - 1] == s2[j - 1]) L[i][j] = L[i - 1][j - 1] + 1
else L[i][j] = max(L[i - 1][j], L[i][j - 1])
}
}
return L[s1.length][s2.length]
}
```