WithourString done

Author: rampatra

src/main/java/com/rampatra/strings/WithoutString.java

@@ -0,0 +1,47 @@
+package com.rampatra.strings;
+
+import com.sun.tools.javac.util.Assert;
+
+/**
+ * Given two strings, base and remove, return a version of the base string where all instances
+ * of the remove string have been removed (not case sensitive). You may assume that the remove
+ * string is length 1 or more. Remove only non-overlapping instances, so with "xxx" removing
+ * "xx" leaves "x".
+ *
+ * @author rampatra
+ * @since 2019-01-23
+ */
+public class WithoutString {
+
+    public static String withoutString(String base, String remove) {
+        String original = base;
+        base = base.toLowerCase();
+        remove = remove.toLowerCase();
+        int baseLen = base.length();
+        int removeLen = remove.length();
+        StringBuilder sb = new StringBuilder();
+
+        for (int i = 0; i < baseLen; ) {
+            int j = 0;
+            // when we see a match, advance the pointer
+            if (base.charAt(i) == remove.charAt(0)) {
+                while (j < removeLen && i + j < baseLen && base.charAt(i + j) == remove.charAt(j)) {
+                    j++;
+                }
+            }
+            if (j == removeLen) { // an entire match was found, move ahead and skip these chars
+                i += removeLen;
+            } else {
+                sb.append(original.charAt(i)); // entire match was not found so append the char to StringBuilder
+                i++;
+            }
+        }
+        return sb.toString();
+    }
+
+    public static void main(String[] args) {
+        Assert.check(withoutString("Hello there", "llo").equals("He there"));
+        Assert.check(withoutString("THIS is a FISH", "is").equals("TH a FH"));
+        Assert.check(withoutString("xxx", "x").equals(""));
+    }
+}