Good question with lots of edge cases, nice

Author: ChSatyaSavith

859. Buddy Strings.cpp

@@ -0,0 +1,38 @@
+class Solution {
+public:
+    bool buddyStrings(string s, string goal)
+    {
+        if(s.length()!=goal.length())
+        {
+            return false;
+        }
+        if(s==goal)
+        {
+            vector<int> count(26,0);
+
+            for(auto x: s)
+            {
+                count[x-'a']++;
+                if(count[x-'a']==2)
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+        vector<int> ans;
+        for(int i = 0;i<s.length();i++)
+        {
+            if(s[i]!=goal[i])
+            {
+                ans.push_back(i);
+            }
+            if(ans.size()>2)
+            {
+                return false;
+            }
+        }
+
+        return ans.size()==2&&s[ans[0]]==goal[ans[1]] && s[ans[1]]==goal[ans[0]];
+    }
+};