feat: 76. Minimum Window Substring

Author: gwbaik9717

minimum-window-substring/gwbaik9717.js

@@ -0,0 +1,75 @@
+// n: len(s), m: len(t)
+// Time complexity: O(n+m)
+// Space complexity: O(n+m)
+
+/**
+ * @param {string} s
+ * @param {string} t
+ * @return {string}
+ */
+var minWindow = function (s, t) {
+  let i = 0;
+  let j = 0;
+
+  const current = new Map();
+  const target = new Map();
+
+  current.set(s[i], 1);
+
+  for (const chr of t) {
+    if (target.has(chr)) {
+      target.set(chr, target.get(chr) + 1);
+      continue;
+    }
+
+    target.set(chr, 1);
+  }
+
+  let answer = null;
+
+  while (i < s.length) {
+    let pass = true;
+    for (const [key, value] of target) {
+      if (!current.has(key)) {
+        pass = false;
+        break;
+      }
+
+      if (current.get(key) < value) {
+        pass = false;
+        break;
+      }
+    }
+
+    if (pass) {
+      if (!answer) {
+        answer = s.slice(i, j + 1);
+      }
+
+      if (answer && j - i + 1 < answer.length) {
+        answer = s.slice(i, j + 1);
+      }
+
+      current.set(s[i], current.get(s[i]) - 1);
+      if (current.get(s[i]) === 0) {
+        current.delete(s[i]);
+      }
+      i++;
+
+      continue;
+    }
+
+    if (j < s.length) {
+      j++;
+      current.set(s[j], (current.get(s[j]) || 0) + 1);
+    } else {
+      break;
+    }
+  }
+
+  if (answer === null) {
+    return "";
+  }
+
+  return answer;
+};