diff --git a/src/store/modules/contest.js b/src/store/modules/contest.js
index f35a9101d..76c47e3b3 100644
--- a/src/store/modules/contest.js
+++ b/src/store/modules/contest.js
@@ -153,7 +153,12 @@ const actions = {
     return new Promise((resolve, reject) => {
       api.getContestProblemList(rootState.route.params.contestID).then(res => {
         res.data.data.sort((a, b) => {
-          return a._id > b._id
+          if (a._id === b._id) {
+            return 0
+          } else if (a._id > b._id) {
+            return 1
+          }
+          return -1
         })
         commit(types.CHANGE_CONTEST_PROBLEMS, {contestProblems: res.data.data})
         resolve(res)
diff --git a/src/utils/time.js b/src/utils/time.js
index 4dc8a5708..1ecd0a255 100644
--- a/src/utils/time.js
+++ b/src/utils/time.js
@@ -18,7 +18,7 @@ function duration (startTime, endTime) {
 
 function secondFormat (seconds) {
   let m = moment.duration(seconds, 'seconds')
-  return m.hours() + ':' + m.minutes() + ':' + m.seconds()
+  return Math.floor(m.asHours()) + ':' + m.minutes() + ':' + m.seconds()
 }
 
 export default {