Added Reformat Phone Number.java

varunu28 · varunu28 · commit 82c3c05883a4 · 2020-12-20T07:30:49.000-08:00
diff --git a/Easy/Reformat Phone Number.java b/Easy/Reformat Phone Number.java
@@ -0,0 +1,29 @@
+class Solution {
+  public String reformatNumber(String number) {
+    List<Character> digits = number.chars().mapToObj(c -> (char) c).filter(Character::isDigit)
+        .collect(Collectors.toList());
+    StringBuilder sb = new StringBuilder();
+    int remainingCharacter = digits.size();
+    int idx = 0;
+    while (remainingCharacter > 4) {
+      for (int i = 0; i < 3; i++) {
+        sb.append(digits.get(idx++));
+      }
+      remainingCharacter -= 3;
+      sb.append("-");
+    }
+    if (remainingCharacter > 3) {
+      for (int i = 0; i < 4; i++) {
+        sb.append(digits.get(idx++));
+        if (i == 1) {
+          sb.append('-');
+        }
+      }
+    } else {
+      for (; idx < digits.size(); idx++) {
+        sb.append(digits.get(idx));
+      }
+    }
+    return sb.toString();
+  }
+}
