Create minimum-number-of-swaps-to-make-the-binary-string-alternating.cpp

Author: kamyu104

C++/minimum-number-of-swaps-to-make-the-binary-string-alternating.cpp

@@ -0,0 +1,30 @@
+// Time:  O(n)
+// Space: O(1)
+
+class Solution {
+public:
+    int minSwaps(string s) {
+        int ones = count(cbegin(s), cend(s), '1');
+        int zeros = size(s) - ones;
+        if (abs(ones - zeros) > 1) {
+            return -1;
+        }
+        if (ones > zeros) {
+            return cost(s, 1);
+        }
+        if (ones < zeros) {
+            return cost(s, 0);
+        }
+        return min(cost(s, 1), cost(s, 0));
+    }
+
+private:
+    int cost(const string& s, int x) {
+        int diff = 0;
+        for (const auto& c : s) {
+            diff += (c - '0' != x);
+            x ^= 1;
+        }
+        return diff / 2;
+    }
+};