Accept Merge Request #250 小 bug 修复 : (virusdefender-dev -> dev)

Merge Request: 小 bug 修复
Created By: @virusdefender
Accepted By: @virusdefender
URL: https://coding.net/u/virusdefender/p/qduoj/git/merge/250

static/src/js/app/oj/problem/problem.js

@@ -120,12 +120,12 @@ require(["jquery", "codeMirror", "csrfToken", "bsAlert", "ZeroClipboard"],
             if (code.indexOf("using namespace std") > -1||code.indexOf("<cstdio>") > -1) {
                 return "2";
             }
-            if (code.indexOf("printf"))
+            if (code.indexOf("printf") > -1)
             {
                 return "1";
             }
             //java
-            if (code.indexOf("public class Main")) {
+            if (code.indexOf("public class Main") > -1) {
                 return "3";
             }
         }