Create relative-sort-array.cpp

Author: kamyu104

C++/relative-sort-array.cpp

@@ -0,0 +1,19 @@
+// Time:  O(nlogn)
+// Space: O(n)
+
+class Solution {
+public:
+    vector<int> relativeSortArray(vector<int>& arr1, vector<int>& arr2) {
+        unordered_map<int, int> lookup;
+        for (int i = 0; i < arr2.size(); ++i) {
+            lookup[arr2[i]] = i;
+        }
+        sort(arr1.begin(), arr1.end(),
+             [&lookup, l = arr2.size()](const auto& a, const auto& b) {
+                 int i = lookup.count(a) ? lookup[a] : l + a;
+                 int j = lookup.count(b) ? lookup[b] : l + b;
+                 return i < j;
+             });
+        return arr1;
+    }
+};