Add Q166

Author: theFool32

166_FractionToRecurringDecimal/FractionToRecurringDecimal.cc

@@ -0,0 +1,28 @@
+class Solution {
+public:
+    string fractionToDecimal(int numerator, int denominator) {
+        string ans;
+        long long n = numerator;
+        long long d = denominator;
+        if (n * d < 0) ans += '-';
+        n = abs(n);
+        d = abs(d);
+        ans += to_string(n/d);
+        if (n % d == 0) return ans;
+
+        ans += '.';
+        unordered_map<int, int> map;
+        for (long long r = n%d; r ; r %= d) {
+            if (map[r] > 0) {
+                ans.insert(map[r], 1, '(');
+                ans += ')';
+                return ans;
+            }
+            map[r] = ans.size();
+            r *= 10;
+
+            ans += to_string(r / d);
+        }
+        return ans;
+    }
+};