Code snippet from The Coding Café - snippet-2.java

snippet-2.java

List<Integer> runningMax = values.stream()
    .gather(Gatherers.scan(
        () -> Integer.MIN_VALUE,  // 1️⃣ Start with smallest possible value
        Integer::max              // 2️⃣ Keep the maximum at each step
    ))
    .toList();

System.out.println("Running maximum: " + runningMax);
// Output: [-2147483648, 1, 5, 5, 8, 8, 9, 9, 9, 9]
//          ↑ initial      ↑ 5>1  ↑ 8>5  ↑ 9>8