Create LargestNumber.cc

speedfirst · speedfirst · commit 75f14bde0929 · 2015-01-14T23:42:53.000+08:00
diff --git a/cpp/LargestNumber.cc b/cpp/LargestNumber.cc
@@ -0,0 +1,28 @@
+
+class Solution {
+public:
+    string largestNumber(vector<int> &num) {
+        vector<string> strs;
+        for (auto i: num) {
+            strs.push_back(to_string(i));
+        }
+        
+        sort(strs.begin(), strs.end(), [](const string& s1, const string& s2) { return s1 + s2 > s2 + s1;}); // note we want desc order
+        string res = "";
+        int i = 0; // ignore leading 0s
+        while (i < strs.size() && strs[i] == "0") {
+            i++;
+        }
+        
+        // if all "0", ...
+        if (i == strs.size()) {
+            return "0";
+        }
+        
+        for (; i < strs.size(); i++) {
+            res += strs[i];
+        }
+    
+        return res;
+    }
+};
