diff --git a/app/controllers/report_controller.rb b/app/controllers/report_controller.rb
--- a/app/controllers/report_controller.rb
+++ b/app/controllers/report_controller.rb
@@ -105,91 +105,87 @@
       end
     end
 
-    if @problem
-      #aggregrate by language
-      @by_lang = {}
-      Submission.where(problem_id: @problem.id).find_each do |sub|
-        lang = Language.find_by_id(sub.language_id)
-        next unless lang
-        next unless sub.points >= @problem.full_score
+    return unless @problem
+
+    @by_lang = {} #aggregrate by language
 
-        #initialize
-        unless @by_lang.has_key?(lang.pretty_name)
-          @by_lang[lang.pretty_name] = {
-            runtime: { avail: false, value: 2**30-1 },
-            memory: { avail: false, value: 2**30-1 },
-            length: { avail: false, value: 2**30-1 },
-            first: { avail: false, value: DateTime.new(3000,1,1) }
-          }
-        end
+    range =65
+    @histogram = { data: Array.new(range,0), summary: {} }
+    @summary = {count: 0, solve: 0, attempt: 0}
+    user = Hash.new(0)
+    Submission.where(problem_id: @problem.id).find_each do |sub|
+      #histogram
+      d = (DateTime.now.in_time_zone - sub.submitted_at) / 24 / 60 / 60
+      @histogram[:data][d.to_i] += 1 if d < range
 
-        if sub.max_runtime and sub.max_runtime < @by_lang[lang.pretty_name][:runtime][:value]
-          @by_lang[lang.pretty_name][:runtime] = {
-            avail: true,
-            user_id: sub.user_id,
-            value: sub.max_runtime,
-            sub_id: sub.id
-          }
-        end
+      @summary[:count] += 1
+      user[sub.user_id] = [user[sub.user_id], (sub.points >= @problem.full_score) ? 1 : 0].max
 
-        if sub.peak_memory and sub.peak_memory < @by_lang[lang.pretty_name][:memory][:value]
-          @by_lang[lang.pretty_name][:memory] = {
-            avail: true,
-            user_id: sub.user_id,
-            value: sub.peak_memory,
-            sub_id: sub.id
-          }
-        end
+      lang = Language.find_by_id(sub.language_id)
+      next unless lang
+      next unless sub.points >= @problem.full_score
 
-        if sub.submitted_at and sub.submitted_at < @by_lang[lang.pretty_name][:first][:value] and
-           !sub.user.admin?
-          @by_lang[lang.pretty_name][:first] = {
-            avail: true,
-            user_id: sub.user_id,
-            value: sub.submitted_at,
-            sub_id: sub.id
-          }
-        end
+      #initialize
+      unless @by_lang.has_key?(lang.pretty_name)
+        @by_lang[lang.pretty_name] = {
+          runtime: { avail: false, value: 2**30-1 },
+          memory: { avail: false, value: 2**30-1 },
+          length: { avail: false, value: 2**30-1 },
+          first: { avail: false, value: DateTime.new(3000,1,1) }
+        }
+      end
 
-        if @by_lang[lang.pretty_name][:length][:value] > sub.effective_code_length
-          @by_lang[lang.pretty_name][:length] = {
-            avail: true,
-            user_id: sub.user_id,
-            value: sub.effective_code_length,
-            sub_id: sub.id
-          }
-        end
-      end
-      
-      #process user_id
-      @by_lang.each do |lang,prop|
-        prop.each do |k,v|
-          v[:user] = User.exists?(v[:user_id]) ? User.find(v[:user_id]).full_name : "(NULL)"
-        end
+      if sub.max_runtime and sub.max_runtime < @by_lang[lang.pretty_name][:runtime][:value]
+        @by_lang[lang.pretty_name][:runtime] = { avail: true, user_id: sub.user_id, value: sub.max_runtime, sub_id: sub.id }
       end
 
-      #sum into best
-      if @by_lang and @by_lang.first
-        @best = @by_lang.first[1].clone
-        @by_lang.each do |lang,prop|
-          if @best[:runtime][:value] >= prop[:runtime][:value]
-            @best[:runtime] = prop[:runtime]
-            @best[:runtime][:lang] = lang
-          end
-          if @best[:memory][:value] >= prop[:memory][:value]
-            @best[:memory] = prop[:memory]
-            @best[:memory][:lang] = lang
-          end
-          if @best[:length][:value] >= prop[:length][:value]
-            @best[:length] = prop[:length]
-            @best[:length][:lang] = lang
-          end
-          if @best[:first][:value] >= prop[:first][:value]
-            @best[:first] = prop[:first]
-            @best[:first][:lang] = lang
-          end
+      if sub.peak_memory and sub.peak_memory < @by_lang[lang.pretty_name][:memory][:value]
+        @by_lang[lang.pretty_name][:memory] = { avail: true, user_id: sub.user_id, value: sub.peak_memory, sub_id: sub.id }
+      end
+
+      if sub.submitted_at and sub.submitted_at < @by_lang[lang.pretty_name][:first][:value] and
+          !sub.user.admin?
+        @by_lang[lang.pretty_name][:first] = { avail: true, user_id: sub.user_id, value: sub.submitted_at, sub_id: sub.id }
+      end
+
+      if @by_lang[lang.pretty_name][:length][:value] > sub.effective_code_length
+        @by_lang[lang.pretty_name][:length] = { avail: true, user_id: sub.user_id, value: sub.effective_code_length, sub_id: sub.id }
+      end
+    end
+
+    #process user_id
+    @by_lang.each do |lang,prop|
+      prop.each do |k,v|
+        v[:user] = User.exists?(v[:user_id]) ? User.find(v[:user_id]).full_name : "(NULL)"
+      end
+    end
+
+    #sum into best
+    if @by_lang and @by_lang.first
+      @best = @by_lang.first[1].clone
+      @by_lang.each do |lang,prop|
+        if @best[:runtime][:value] >= prop[:runtime][:value]
+          @best[:runtime] = prop[:runtime]
+          @best[:runtime][:lang] = lang
+        end
+        if @best[:memory][:value] >= prop[:memory][:value]
+          @best[:memory] = prop[:memory]
+          @best[:memory][:lang] = lang
+        end
+        if @best[:length][:value] >= prop[:length][:value]
+          @best[:length] = prop[:length]
+          @best[:length][:lang] = lang
+        end
+        if @best[:first][:value] >= prop[:first][:value]
+          @best[:first] = prop[:first]
+          @best[:first][:lang] = lang
         end
       end
     end
+
+    @histogram[:summary][:max] = [@histogram[:data].max,1].max
+    @summary[:attempt] = user.count
+    user.each_value { |v| @summary[:solve] += 1 if v == 1 }
   end
+
 end