Data commit

Task/Equilibrium-index/Swift/equilibrium-index.swift

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+extension Collection where Element: Numeric {
+  func equilibriumIndexes() -> [Index] {
+    guard !isEmpty else {
+      return []
+    }
+
+    let sumAll = reduce(0, +)
+    var ret = [Index]()
+    var sumLeft: Element = 0
+    var sumRight: Element
+
+    for i in indices {
+      sumRight = sumAll - sumLeft - self[i]
+
+      if sumLeft == sumRight {
+        ret.append(i)
+      }
+
+      sumLeft += self[i]
+    }
+
+    return ret
+  }
+}
+
+let arr = [-7, 1, 5, 2, -4, 3, 0]
+
+print("Equilibrium indexes of \(arr): \(arr.equilibriumIndexes())")