Create 0097-interleaving-string.kt

Author: a93a

kotlin/0097-interleaving-string.kt

@@ -0,0 +1,56 @@
+//DP 
+class Solution {
+    fun isInterleave(s1: String, s2: String, s3: String): Boolean {
+
+        val dp = Array(s1.length + 1) { BooleanArray(s2.length + 1) }
+        val n = s1.length
+        val m = s2.length
+
+        if(n + m != s3.length) return false
+
+        dp[n][m] = true
+
+        for (i in n downTo 0) {
+            for (j in m downTo 0) {
+                if (i < n && s1[i] == s3[i+j] && dp[i + 1][j])
+                    dp[i][j] = true
+                if (j < m && s2[j] == s3[i+j] && dp[i][j + 1])
+                    dp[i][j] = true
+            }
+        }
+    
+        return dp[0][0]
+    }
+}
+
+//DFS with memoization
+class Solution {
+    fun isInterleave(s1: String, s2: String, s3: String): Boolean {
+
+        if(s1.length + s2.length != s3.length) return false
+
+        val memo = Array(s1.length + 1) { BooleanArray(s2.length + 1) }
+        val n = s1.length
+        val m = s2.length
+
+        fun dfs(i: Int, j: Int): Boolean {
+
+            if (i == n && j == m) return true
+            if (memo[i][j] == true) return false
+
+            if (i < n && s1[i] == s3[i+j]) {
+                if (dfs(i + 1, j))
+                    return true
+            }
+            if (j < m && s2[j] == s3[i+j]) {
+                if (dfs(i, j + 1))
+                    return true
+            }
+         
+            memo[i][j] = true
+            return false
+        }
+
+        return dfs(0,0)
+    }
+}