Add solution #76

Author: JoshCrozier

README.md

@@ -81,6 +81,7 @@
 73|[Set Matrix Zeroes](./0073-set-matrix-zeroes.js)|Medium|
 74|[Search a 2D Matrix](./0074-search-a-2d-matrix.js)|Medium|
 75|[Sort Colors](./0075-sort-colors.js)|Medium|
+76|[Minimum Window Substring](./0076-minimum-window-substring.js)|Hard|
 77|[Combinations](./0077-combinations.js)|Medium|
 78|[Subsets](./0078-subsets.js)|Medium|
 79|[Word Search](./0079-word-search.js)|Medium|

solutions/0076-minimum-window-substring.js

@@ -0,0 +1,44 @@
+/**
+ * 76. Minimum Window Substring
+ * https://leetcode.com/problems/minimum-window-substring/
+ * Difficulty: Hard
+ *
+ * Given two strings s and t of lengths m and n respectively, return the minimum window substring
+ * of s such that every character in t (including duplicates) is included in the window. If there
+ * is no such substring, return the empty string "".
+ *
+ * The testcases will be generated such that the answer is unique.
+ */
+
+/**
+ * @param {string} s
+ * @param {string} t
+ * @return {string}
+ */
+var minWindow = function(s, t) {
+  const values = new Array(128).fill(0);
+  let [start, end] = [-Infinity, Infinity];
+
+  for (let i = 0; i < t.length; i++) {
+    values[t.charCodeAt(i)]++;
+  }
+
+  for (let i = 0, j = 0, total = t.length; i < s.length; i++) {
+    if (values[s.charCodeAt(i)] > 0) {
+      total--;
+    }
+    values[s.charCodeAt(i)]--;
+    while (!total) {
+      if (end - start > i - j) {
+        [start, end] = [j, i];
+      }
+      values[s.charCodeAt(j)]++;
+      if (values[s.charCodeAt(j)] > 0) {
+        total++;
+      }
+      j++;
+    }
+  }
+
+  return end !== Infinity ? s.slice(start, end + 1) : '';
+};