From b9153e2708f5e32d3f5f5d0ba3142827042eb3cf Mon Sep 17 00:00:00 2001
From: falsycat <me@falsy.cat>
Date: Sun, 30 Mar 2025 08:56:14 +0900
Subject: [PATCH] fix an issue in findSegment

---
 src/hncore/Digraph.zig | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/hncore/Digraph.zig b/src/hncore/Digraph.zig
index 24c5bcb..44ec4df 100644
--- a/src/hncore/Digraph.zig
+++ b/src/hncore/Digraph.zig
@@ -72,6 +72,12 @@ pub fn Digraph(comptime T: type, comptime lessThanFn: LessThanFunc(T)) type {
 
         }
 
+        ///
+        pub fn getChildrenOf(self: *const @This(), from: T) []const Conn {
+            const begin, const end = self.findSegment(from);
+            return self.map.items[begin..end];
+        }
+
         fn findConnectionInSegment(self: *const @This(), from: T, to: T, begin: usize, end: usize) ?usize {
             for (self.map.items[begin..end], begin..) |v, idx| {
                 if ((v.from == from) and (v.to == to)) {
@@ -93,14 +99,14 @@ pub fn Digraph(comptime T: type, comptime lessThanFn: LessThanFunc(T)) type {
             var end  : usize = undefined;
             if (baseFrom < from) {
                 begin = baseIdx;
-                while ((begin < n) and (self.map.items[begin].from != from)) { begin += 1; }
+                while ((begin < n) and (self.map.items[begin].from < from)) { begin += 1; }
 
                 end = begin;
                 while ((end < n) and (self.map.items[end].from == from)) { end += 1; }
 
             } else if (baseFrom > from) {
                 end = baseIdx;
-                while ((end > 0) and (self.map.items[end-1].from != from)) { end -= 1; }
+                while ((end > 0) and (self.map.items[end-1].from > from)) { end -= 1; }
 
                 begin = end;
                 while ((begin > 0) and (self.map.items[begin-1].from == from)) { begin -= 1; }
@@ -256,20 +262,23 @@ test "chaotic operation" {
     defer sut.deinit();
 
     const N = 100;
+    const P = 109;
+    const Q = 113;
+    const R = 127;
     for (0..N) |v| {
         const x: Sut.Node = @intCast(v);
-        try sut.connect(x*%7, x*%13);
+        try sut.connect((x*Q)%P, (x*R)%P);
     }
     for (N/2..N) |v| {
         const x: Sut.Node = @intCast(v);
-        try sut.disconnect(x*%7, x*%13);
+        try sut.disconnect((x*Q)%P, (x*R)%P);
     }
     for (0..N/2) |v| {
         const x: Sut.Node = @intCast(v);
-        try std.testing.expect(sut.isConnected(x*%7, x*%13));
+        try std.testing.expect(sut.isConnected((x*Q)%P, (x*R)%P));
     }
     for (N/2..N) |v| {
         const x: Sut.Node = @intCast(v);
-        try std.testing.expect(!sut.isConnected(x*%7, x*%13));
+        try std.testing.expect(!sut.isConnected((x*Q)%P, (x*R)%P));
     }
 }