Add solution to 'a lot' of problems

Easy/shuffle-string/solution.cpp

@@ -0,0 +1,23 @@
+#include <string>
+#include <vector>
+
+class Solution {
+public:
+    std::string restoreString(std::string s, std::vector<int> &indices) {
+        for (int i = 1; i < indices.size(); i++) {
+            int itmp = indices[i];
+            char ctmp = s[i];
+            int j = i - 1;
+
+            while (j >= 0 && indices[j] > itmp) {
+                indices[j + 1] = indices[j];
+                s[j + 1] = s[j];
+                j = j - 1;
+            }
+            indices[j + 1] = itmp;
+            s[j + 1] = ctmp;
+        }
+
+        return s;
+    }
+};