The + seems optional for relative times

See the CLICS spec: https://github.com/icpc/ccs-specs/blame/master/Contest_API.md#L235.

Author: vmcj

webapp/src/Validator/Constraints/TimeStringValidator.php

@@ -25,8 +25,8 @@ public function validate(mixed $value, Constraint $constraint): void
 
         if ($constraint->allowRelative) {
             $regex   = $constraint->relativeIsPositive ?
-                "/^(\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d(\.\d{2,6})? [A-Za-z][A-Za-z0-9_\/+-]{1,35}|\+" . $relativeRegex . ")$/" :
-                "/^(\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d(\.\d{1,6})? [A-Za-z][A-Za-z0-9_\/+-]{1,35}|-"  . $relativeRegex . ")$/";
+                "/^(\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d(\.\d{2,6})? [A-Za-z][A-Za-z0-9_\/+-]{1,35}|\+?" . $relativeRegex . ")$/" :
+                "/^(\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d(\.\d{1,6})? [A-Za-z][A-Za-z0-9_\/+-]{1,35}|-"   . $relativeRegex . ")$/";
             $message = $constraint->absoluteRelativeMessage;
         } else {
             $regex   = "/^\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d(\.\d{1,6})? [A-Za-z][A-Za-z0-9_\/+-]{1,35}$/";