Add solution #761

Author: JoshCrozier

README.md

@@ -575,6 +575,7 @@
 754|[Reach a Number](./0754-reach-a-number.js)|Medium|
 756|[Pyramid Transition Matrix](./0756-pyramid-transition-matrix.js)|Medium|
 757|[Set Intersection Size At Least Two](./0757-set-intersection-size-at-least-two.js)|Hard|
+761|[Special Binary String](./0761-special-binary-string.js)|Hard|
 762|[Prime Number of Set Bits in Binary Representation](./0762-prime-number-of-set-bits-in-binary-representation.js)|Easy|
 763|[Partition Labels](./0763-partition-labels.js)|Medium|
 783|[Minimum Distance Between BST Nodes](./0783-minimum-distance-between-bst-nodes.js)|Easy|

solutions/0761-special-binary-string.js

@@ -0,0 +1,41 @@
+/**
+ * 761. Special Binary String
+ * https://leetcode.com/problems/special-binary-string/
+ * Difficulty: Hard
+ *
+ * Special binary strings are binary strings with the following two properties:
+ * - The number of 0's is equal to the number of 1's.
+ * - Every prefix of the binary string has at least as many 1's as 0's.
+ *
+ * You are given a special binary string s.
+ *
+ * A move consists of choosing two consecutive, non-empty, special substrings of s,
+ * and swapping them. Two strings are consecutive if the last character of the first
+ * string is exactly one index before the first character of the second string.
+ *
+ * Return the lexicographically largest resulting string possible after applying
+ * the mentioned operations on the string.
+ */
+
+/**
+ * @param {string} s
+ * @return {string}
+ */
+function makeLargestSpecial(s) {
+  if (s.length <= 2) return s;
+
+  let count = 0;
+  let start = 0;
+  const specials = [];
+
+  for (let i = 0; i < s.length; i++) {
+    count += s[i] === '1' ? 1 : -1;
+
+    if (count === 0) {
+      specials.push('1' + makeLargestSpecial(s.slice(start + 1, i)) + '0');
+      start = i + 1;
+    }
+  }
+
+  return specials.sort().reverse().join('');
+}