adding algo

src/my_project/interviews/top_150_questions_round_22/ex_141_interleaving_string.py

@@ -0,0 +1,16 @@
+class Solution:
+    def isInterleave(self, s1: str, s2: str, s3: str) -> bool:
+        m, n = len(s1), len(s2)
+        if m + n != len(s3):
+            return False
+        dp = [False] * (n + 1)
+        dp[0] = True
+        for j in range(1, n + 1):
+            dp[j] = dp[j - 1] and s2[j - 1] == s3[j - 1]
+        for i in range(1, m + 1):
+            dp[0] = dp[0] and s1[i - 1] == s3[i - 1]
+            for j in range(1, n + 1):
+                dp[j] = (dp[j] and s1[i - 1] == s3[i + j - 1]) or \
+                         (dp[j - 1] and s2[j - 1] == s3[i + j - 1])
+        return dp[n]
+

src/my_project/interviews_typescript/top_150_questions_round_1/ex_141_interleaving_string.ts

@@ -0,0 +1,17 @@
+function isInterleave(s1: string, s2: string, s3: string): boolean {
+    const m = s1.length, n = s2.length;
+    if (m + n !== s3.length) return false;
+    const dp: boolean[] = new Array(n + 1).fill(false);
+    dp[0] = true;
+    for (let j = 1; j <= n; j++) {
+        dp[j] = dp[j - 1] && s2[j - 1] === s3[j - 1];
+    }
+    for (let i = 1; i <= m; i++) {
+        dp[0] = dp[0] && s1[i - 1] === s3[i - 1];
+        for (let j = 1; j <= n; j++) {
+            dp[j] = (dp[j] && s1[i - 1] === s3[i + j - 1]) ||
+                    (dp[j - 1] && s2[j - 1] === s3[i + j - 1]);
+        }
+    }
+    return dp[n];
+};

tests/test_150_questions_round_22/test_141_interleaving_string_round_22.py

@@ -0,0 +1,24 @@
+import unittest
+from src.my_project.interviews.top_150_questions_round_22\
+.ex_141_interleaving_string import Solution
+
+
+class InterleavingStringTestCase(unittest.TestCase):
+    def setUp(self):
+        self.solution = Solution()
+
+    def test_example1(self):
+        self.assertTrue(self.solution.isInterleave("aabcc", "dbbca", "aadbbcbcac"))
+
+    def test_example2(self):
+        self.assertFalse(self.solution.isInterleave("aabcc", "dbbca", "aadbbbaccc"))
+
+    def test_empty_strings(self):
+        self.assertTrue(self.solution.isInterleave("", "", ""))
+
+    def test_wrong_length(self):
+        self.assertFalse(self.solution.isInterleave("a", "b", "abc"))
+
+    def test_one_empty(self):
+        self.assertTrue(self.solution.isInterleave("", "abc", "abc"))
+        self.assertTrue(self.solution.isInterleave("abc", "", "abc"))