Update all new Tasks

Task/String-matching/Groovy/string-matching.groovy

@@ -0,0 +1,23 @@
+assert "abcd".startsWith("ab")
+assert ! "abcd".startsWith("zn")
+assert "abcd".endsWith("cd")
+assert ! "abcd".endsWith("zn")
+assert "abab".contains("ba")
+assert ! "abab".contains("bb")
+
+
+assert "abab".indexOf("bb") == -1 // not found flag
+assert "abab".indexOf("ab") == 0
+
+def indicesOf = { string, substring ->
+    if (!string) { return [] }
+    def indices = [-1]
+    while (true) {
+        indices << string.indexOf(substring, indices.last()+1)
+        if (indices.last() == -1) break
+    }
+    indices[1..<(indices.size()-1)]
+}
+assert indicesOf("abab", "ab") == [0, 2]
+assert indicesOf("abab", "ba") == [1]
+assert indicesOf("abab", "xy") == []