优化异界分组算法

script/module/anotherWorldBattle/AnotherWorldBattleCS.lua

@@ -152,6 +152,8 @@ local function groupingAlgorithm(unionArray, len)
 
         for i=1, cnt do
             local correctTb = checkRandIdx(startIdx, endIdx)
+            if #correctTb == 0 then break end
+
             local matchIdx = correctTb[math.random(1, #correctTb)]
             usedTb[currentIdx] = true
             usedTb[matchIdx] = true