Feat: 76. Minimum Window Substring

minimum-window-substring/HC-kang.ts

@@ -0,0 +1,44 @@
+/**
+ * https://leetcode.com/problems/minimum-window-substring
+ * T.C. O(s + t)
+ * S.C. O(t)
+ */
+function minWindow(s: string, t: string): string {
+  let minLow = 0;
+  let minHigh = s.length;
+
+  const counts: Record<string, number> = {};
+  for (const c of t) {
+    counts[c] = (counts[c] || 0) + 1;
+  }
+
+  let included = 0;
+
+  let low = 0;
+  for (let high = 0; high < s.length; high++) {
+    if (counts[s[high]]) {
+      if (counts[s[high]] > 0) {
+        included++;
+      }
+      counts[s[high]]--;
+    }
+
+    while (included === t.length) {
+      if (high - low < minHigh - minLow) {
+        minLow = low;
+        minHigh = high;
+      }
+
+      if (counts[s[low]]) {
+        counts[s[low]]++;
+        if (counts[s[low]] > 0) {
+          included--;
+        }
+      }
+
+      low++;
+    }
+  }
+
+  return minHigh === s.length ? '' : s.substring(minLow, minHigh + 1);
+}