5. Minimum Window Substring

Author: Sunjae95

minimum-window-substring/sunjae.js

@@ -0,0 +1,41 @@
+/**
+ * @description
+ * brainstorming:
+ * two pointer + hash table
+ *
+ * n = length of s
+ * m = length of t
+ * time complexity: O(n*n)
+ * space complexity: O(n)
+ */
+var minWindow = function (s, t) {
+  const requiredMap = t.split("").reduce((map, char) => {
+    map.set(char, (map.get(char) ?? 0) + 1);
+    return map;
+  }, new Map());
+  const requiredArray = [...requiredMap.entries()];
+  const map = new Map();
+  const successRequired = () =>
+    requiredArray.every(([key, value]) => map.get(key) >= value);
+
+  let answer = "";
+  let start = 0;
+
+  for (let i = 0; i < s.length; i++) {
+    if (requiredMap.has(s[i])) map.set(s[i], (map.get(s[i]) ?? 0) + 1);
+
+    while (successRequired()) {
+      const now = s.slice(start, i + 1);
+      answer = answer === "" || answer.length >= now.length ? now : answer;
+
+      if (map.has(s[start])) {
+        map.set(s[start], map.get(s[start]) - 1);
+        if (map.get(s[start]) === -1) map.delete(s[start]);
+      }
+
+      start++;
+    }
+  }
+
+  return answer;
+};