Create sort-integers-by-the-number-of-1-bits.cpp

Author: kamyu104

C++/sort-integers-by-the-number-of-1-bits.cpp

@@ -0,0 +1,14 @@
+// Time:  O(nlogn)
+// Space: O(1)
+
+class Solution {
+public:
+    vector<int> sortByBits(vector<int>& arr) {
+        sort(begin(arr), end(arr),
+             [](const auto& a, const auto& b) {
+                 return make_pair(__builtin_popcount(a), a) <
+                        make_pair(__builtin_popcount(b), b);
+             });
+        return arr;
+    }
+};