Add solution #664

Author: JoshCrozier

README.md

@@ -499,6 +499,7 @@
 659|[Split Array into Consecutive Subsequences](./0659-split-array-into-consecutive-subsequences.js)|Medium|
 661|[Image Smoother](./0661-image-smoother.js)|Easy|
 662|[Maximum Width of Binary Tree](./0662-maximum-width-of-binary-tree.js)|Medium|
+664|[Strange Printer](./0664-strange-printer.js)|Hard|
 680|[Valid Palindrome II](./0680-valid-palindrome-ii.js)|Easy|
 684|[Redundant Connection](./0684-redundant-connection.js)|Medium|
 686|[Repeated String Match](./0686-repeated-string-match.js)|Easy|

solutions/0664-strange-printer.js

@@ -0,0 +1,35 @@
+/**
+ * 664. Strange Printer
+ * https://leetcode.com/problems/strange-printer/
+ * Difficulty: Hard
+ *
+ * There is a strange printer with the following two special properties:
+ * - The printer can only print a sequence of the same character each time.
+ * - At each turn, the printer can print new characters starting from and ending at any place and
+ *   will cover the original existing characters.
+ *
+ * Given a string s, return the minimum number of turns the printer needed to print it.
+ */
+
+/**
+ * @param {string} s
+ * @return {number}
+ */
+var strangePrinter = function(s) {
+  const n = s.length;
+  const dp = new Array(n).fill().map(() => new Array(n).fill(0));
+
+  for (let i = n - 1; i >= 0; i--) {
+    dp[i][i] = 1;
+    for (let j = i + 1; j < n; j++) {
+      dp[i][j] = dp[i][j - 1] + 1;
+      for (let k = i; k < j; k++) {
+        if (s[k] === s[j]) {
+          dp[i][j] = Math.min(dp[i][j], dp[i][k] + (k + 1 <= j - 1 ? dp[k + 1][j - 1] : 0));
+        }
+      }
+    }
+  }
+
+  return dp[0][n - 1];
+};