Update Swift/438. Find All Anagrams in a String.swift

Author: liuchuo

Swift/438. Find All Anagrams in a String.swift

@@ -0,0 +1,40 @@
+// 438. Find All Anagrams in a String
+// 4120 ms
+
+func findAnagrams(_ s: String, _ p: String) -> [Int] {
+    let n = p.count
+    var arr = Array(repeating: 0, count: s.count) , i = 0, c: Character, j = 0
+
+    var pArr = Array(repeating: 0, count: 26)
+    p.utf8.forEach({ pArr[Int($0-97)] += 1 })
+    let pSet = pArr.enumerated().filter({$0.element > 0}).map({ Character(UnicodeScalar($0.offset + 97)!)  })
+
+    while i + n <= s.count {
+        let start = s.index(s.startIndex, offsetBy: i)
+        let end = s.index(s.startIndex, offsetBy: i + n)
+        c = s[start]
+        let t = s[start..<end]
+
+        var tArr = Array(repeating: 0, count: 26)
+        t.utf8.forEach({ tArr[Int($0-97)] += 1 })
+
+        if tArr == pArr {
+            arr[j] = i; j += 1
+            while i + n < s.count {
+                let c1 = s[s.index(s.startIndex, offsetBy: i + n)]
+                if c == c1 {
+                    i += 1
+                    c = s[s.index(s.startIndex, offsetBy: i)]
+                    arr[j] = i; j += 1
+                } else if !pSet.contains(c1) {
+                    i += n; break
+                } else {
+                    break
+                }
+            }
+        }
+        i += 1
+    }
+
+    return Array(arr[0..<j])
+}