fix integer overflow issue

Author: haoel

src/factorialTrailingZeroes/factorialTrailingZeroes.cpp

@@ -64,7 +64,8 @@ class Solution {
     public:
         int trailingZeroes(int n) {
             int result = 0;
-            for(int i=5; n/i>0; i*=5){
+            //To avoid the integer overflow ( e.g. 'n >=1808548329' )
+            for(int i=5; n/i>0 && i <= INT_MAX/5; i*=5){
                 result += (n/i);
             }
             return result;