Update next-permutation.cpp

Author: kamyu104

C++/next-permutation.cpp

@@ -18,17 +18,20 @@ class Solution {
         while (pivot != rend && *pivot >= *prev(pivot)) {
             ++pivot;
         }
-        
+
+        bool is_greater = true;
         if (pivot != rend) {
             // Find the number which is greater than pivot, and swap it with pivot
             auto change = find_if(rbegin, pivot, bind1st(less<int>(), *pivot));
             swap(*change, *pivot);
+        } else {
+            is_greater = false;
         }
 
         // Make the sequence after pivot non-descending
         reverse(rbegin, pivot);
 
-        return true;
+        return is_greater;
     }
 };