✅ [1456] prefix sum

Author: enkr1

1456/my_solution.js

@@ -4,19 +4,25 @@
  * @return {number}
  */
 var maxVowels = function (s, k) {
-  let l = 0, maxCount = 0, vowelSet = new Set(["a", "e", "i", "o", "u"])
+  let l = 0, maxCount = 0, vowelSet = new Set(["a", "e", "i", "o", "u"]), acc = []
   s = s.split("")
   console.log(s)
   console.log(vowelSet)
 
-  while ((l + k - 1) < s.length) {
-    let tmpCount = 0;
-    for (let i = l; i < (l + k); i++) {
-      if (vowelSet.has(s[i])) tmpCount++;
-    }
+  let tmpSum = 0;
+  for (let i = 0; i < s.length; i++) {
+    tmpSum += (vowelSet.has(s[i]) ? 1 : 0)
+    acc[i] = tmpSum;
+  }
 
-    maxCount = Math.max(maxCount, tmpCount)
+  console.log(acc)
 
+  while ((l + k - 1) < s.length) {
+    // console.log("___")
+    // console.log(acc[k - 1])
+    // console.log((acc[l - 1] ?? 0))
+    // console.log(acc[k - 1] - (acc[l - 1] ?? 0))
+    maxCount = Math.max(maxCount, acc[(k + l) - 1] - (acc[l - 1] ?? 0))
     l++;
   }
 
@@ -28,8 +34,8 @@ var maxVowels = function (s, k) {
 // ['a', 'b', 'c', 'i', 'i', 'i', 'd', 'e', 'f']
 let x =
   // maxVowels("abciiidef", 3)//3
-  // maxVowels("aeiou", 2) //2
-  maxVowels("leetcode", 3) //2
+// maxVowels("aeiou", 2) //2
+maxVowels("leetcode", 3) //2
 
-  console.log("Res")
-  console.log(x)
+console.log("Res")
+console.log(x)

1456/solution.js

@@ -0,0 +1,22 @@
+/**
+ * @param {string} s
+ * @param {number} k
+ * @return {number}
+ */
+var maxVowels = function (s, k) {
+  let l = 0, maxCount = 0, vowelSet = new Set(["a", "e", "i", "o", "u"]), acc = []
+  s = s.split("")
+
+  let tmpSum = 0;
+  for (let i = 0; i < s.length; i++) {
+    tmpSum += (vowelSet.has(s[i]) ? 1 : 0)
+    acc[i] = tmpSum;
+  }
+
+  while ((l + k - 1) < s.length) {
+    maxCount = Math.max(maxCount, acc[(k + l) - 1] - (acc[l - 1] ?? 0))
+    l++;
+  }
+
+  return maxCount
+};