master > master: code-rust - schönheits op für algorithmus

code/rust/src/core/utils.rs

@@ -25,11 +25,22 @@ pub fn construct_regex(pattern: &str) -> Regex {
 // METHODS values
 // ----------------------------------------------------------------
 
-pub fn min<T>(x: T, y: T) -> T
-    where T: PartialOrd
-{
-    return if y < x { y } else { x };
+#[macro_export]
+macro_rules! value_min{
+    ($value:expr $(,)?)=>{ $value };
+    ($value:expr $(, $values:expr)+ $(,)?)=>{
+        {
+            let x = $crate::value_min!($( $values )+);
+            if $value < x {
+                $value
+            } else {
+                x
+            }
+        }
+    };
 }
+#[allow(unused_imports)]
+pub(crate) use value_min;
 
 // ----------------------------------------------------------------
 // METHODS Vectors

code/rust/src/graphs/tarjan.rs

@@ -6,7 +6,7 @@ use std::fmt::Display;
 use std::hash::Hash;
 use std::collections::HashMap;
 
-use crate::core::utils;
+use crate::value_min;
 use crate::core::log::log_debug;
 use crate::stacks::stack::Stack;
 use crate::graphs::graph::Graph;
@@ -44,10 +44,15 @@ pub fn tarjan_algorithm<T>(gph: &Graph<T>, debug: bool) -> Vec<Vec<T>>
 fn tarjan_visit<T>(gph: &Graph<T>, v: &T, ctx: &mut Context<T>)
     where T: Eq + Hash + Clone + Copy + Display
 {
-    if !(ctx.get_state(v) == State::UNTOUCHED) {
-        return;
-    }
+    // do nothing, if v already visited
+    if !(ctx.get_state(v) == State::UNTOUCHED) { return; }
 
+    /****************
+     * First visit of v.
+     * - Place v on stack.
+     * - Initialise visit-index + component-index.
+     * - After each rekursiv call, only those  all
+     ****************/
     ctx.max_index += 1;
     ctx.push(v);
     ctx.set_root(v, ctx.max_index);
@@ -57,13 +62,12 @@ fn tarjan_visit<T>(gph: &Graph<T>, v: &T, ctx: &mut Context<T>)
     // depth first search:
     for u in gph.successors(&v) {
         tarjan_visit(gph, &u, ctx);
-        // remains relevant for v, provided u still in Stack:
-        if ctx.stack.elements.contains(&u) {
-            let root = utils::min(
-                ctx.get_root(&u),
-                ctx.get_root(v)
-            );
-            ctx.set_root(v, root);
+        /****
+         * u is in the same component as v, if and only if u is still on the stack.
+         * In this case, update the associated component-index of v:
+         ****/
+        if ctx.stack.contains(&u) {
+            ctx.set_root(v, value_min!(ctx.get_root(v), ctx.get_root(&u)));
         }
     }
     ctx.set_state(v, State::FINISHED);
@@ -169,8 +173,8 @@ impl<T> Context<T>
     }
 
     fn log_info(self: &Self, u: &T) {
-        if !self.debug { return; }
         let info = self.get_info(&u);
+        if !self.debug { return; }
         log_debug!("node, index, component: ({}, {}, {})", info.node, info.index, info.root);
     }
 }

code/rust/src/stacks/stack.rs

@@ -18,7 +18,7 @@ pub struct Stack<T> {
 }
 
 impl<T> Stack<T>
-where T: Clone + ToString {
+where T: Clone + ToString + Eq {
     /// Creates new typed instance of stack.
     pub fn new() -> Stack<T> {
         return Stack {
@@ -53,6 +53,11 @@ where T: Clone + ToString {
         return element;
     }
 
+    /// checks if element in stack:
+    pub fn contains(self: &Self, element: &T) -> bool {
+        return self.elements.contains(element);
+    }
+
     /// convert entries to strings
     #[allow(dead_code)]
     fn repr(self: &Self) -> Vec<String> {

code/rust/tests/test_core/test_utils.rs

@@ -3,6 +3,7 @@
 // ----------------------------------------------------------------
 
 use ads2::core::utils;
+use ads2::value_min;
 
 // ----------------------------------------------------------------
 // Test regex
@@ -21,11 +22,11 @@ fn test_regex() {
 
 #[test]
 fn test_min() {
-    assert_eq!(utils::min("beth", "alef"), "alef");
-    assert_eq!(utils::min("alef", "beth"), "alef");
-    assert_eq!(utils::min("alef", "ale"), "ale");
-    assert_eq!(utils::min(320, 24), 24);
-    assert_eq!(utils::min(0.03, 0.2), 0.03);
+    assert_eq!(value_min!("beth", "alef"), "alef");
+    assert_eq!(value_min!("alef", "beth"), "alef");
+    assert_eq!(value_min!("alef", "ale"), "ale");
+    assert_eq!(value_min!(320, 24), 24);
+    assert_eq!(value_min!(0.03, 0.2), 0.03);
 }
 
 // ----------------------------------------------------------------