Data update

Task/Stern-Brocot-sequence/Zig/stern-brocot-sequence.zig

@@ -0,0 +1,81 @@
+const std = @import("std");
+
+fn gcd(a: u64, b: u64) u64 {
+    if (b == 0) return a;
+    return gcd(b, a % b);
+}
+
+fn sternBrocot(allocator: std.mem.Allocator, up_to: u64) !std.ArrayList(u64) {
+    var seq = std.ArrayList(u64).init(allocator);
+    try seq.append(1);
+    try seq.append(1);
+
+    var last: u64 = 1;
+    var idx: usize = 1;
+
+    while (last < up_to) {
+        last = seq.items[idx];
+        try seq.append(last + seq.items[idx - 1]);
+        try seq.append(last);
+        idx += 1;
+    }
+
+    return seq;
+}
+
+fn testSternBrocot() !void {
+    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+    defer arena.deinit();
+    const allocator = arena.allocator();
+
+    var seq = try sternBrocot(allocator, 100);
+
+    // Print first 15 in sequence
+    std.debug.print("First 15 in sequence: ", .{});
+    std.debug.print("[", .{});
+    for (seq.items[0..15], 0..) |val, i| {
+        if (i > 0) std.debug.print(", ", .{});
+        std.debug.print("{d}", .{val});
+    }
+    std.debug.print("]\n", .{});
+
+    // Print first positions of integers 1 through 10
+    std.debug.print("First positions of integers 1 through 10:\n", .{});
+    for (1..11) |i| {
+        const i_u64 = @as(u64, i);
+        var found = false;
+        for (seq.items, 0..) |val, pos| {
+            if (val == i_u64) {
+                std.debug.print("    {d:>2} at position {d}\n", .{i, pos + 1});
+                found = true;
+                break;
+            }
+        }
+        if (!found) {
+            std.debug.print("Error finding position of {d}\n", .{i});
+        }
+    }
+
+    // Find position of 100
+    for (seq.items, 0..) |val, pos| {
+        if (val == 100) {
+            std.debug.print("   100 at position {d}\n", .{pos + 1});
+            break;
+        }
+    }
+
+    // Check if first 999 consecutive pairs have gcd of 1
+    var all_gcd_one = true;
+    for (1..1000) |i| {
+        if (i >= seq.items.len) break;
+        if (gcd(seq.items[i - 1], seq.items[i]) != 1) {
+            all_gcd_one = false;
+            break;
+        }
+    }
+    std.debug.print("The first 999 consecutive pairs have gcd of 1: {any}.\n", .{all_gcd_one});
+}
+
+pub fn main() !void {
+    try testSternBrocot();
+}