Data commit

Task/Combinations/Kotlin/combinations-1.kotlin

@@ -0,0 +1,25 @@
+class Combinations(val m: Int, val n: Int) {
+    private val combination = IntArray(m)
+
+    init {
+        generate(0)
+    }
+
+    private fun generate(k: Int) {
+        if (k >= m) {
+            for (i in 0 until m) print("${combination[i]} ")
+            println()
+        }
+        else {
+            for (j in 0 until n)
+                if (k == 0 || j > combination[k - 1]) {
+                    combination[k] = j
+                    generate(k + 1)
+                }
+        }
+    }
+}
+
+fun main(args: Array<String>) {
+    Combinations(3, 5)
+}

Task/Combinations/Kotlin/combinations-2.kotlin

@@ -0,0 +1,28 @@
+import java.util.LinkedList
+
+inline fun <reified T> combinations(arr: Array<T>, m: Int) = sequence {
+    val n = arr.size
+    val result = Array(m) { arr[0] }
+    val stack = LinkedList<Int>()
+    stack.push(0)
+    while (stack.isNotEmpty()) {
+        var resIndex = stack.size - 1;
+        var arrIndex = stack.pop()
+
+        while (arrIndex < n) {
+            result[resIndex++] = arr[arrIndex++]
+            stack.push(arrIndex)
+
+            if (resIndex == m) {
+                yield(result.toList())
+                break
+            }
+        }
+    }
+}
+
+fun main() {
+    val n = 5
+    val m = 3
+    combinations((1..n).toList().toTypedArray(), m).forEach { println(it.joinToString(separator = " ")) }
+}