8a13efde83
* update zig in chapters 1-6 * fix zig dijkstras algo * fix zig greedy algo * fix longest_common_subsequence in zig * cleanup * test: use testing allocator
38 lines
977 B
Zig
38 lines
977 B
Zig
const std = @import("std");
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const print = std.debug.print;
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const expect = std.testing.expect;
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pub fn main() void {
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const my_list = &[_]i8{ 1, 3, 5, 7, 9 };
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print("{?}\n", .{binarySearch(i8, my_list, 3)});
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print("{?}\n", .{binarySearch(i8, my_list, -1)});
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}
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fn binarySearch(comptime T: type, list: []const T, item: T) ?usize {
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var low: i32 = 0;
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const u_high: u32 = @truncate(list.len);
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var high: i32 = @intCast(u_high - 1);
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return while (low <= high) {
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const mid = @divTrunc((low + high), 2);
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const m: usize = @intCast(mid);
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const guess = list[m];
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if (guess == item) break m;
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if (guess > item) {
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high = mid - 1;
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} else low = mid + 1;
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} else null;
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}
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test "binarySearch" {
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const my_list = &[_]i8{ 1, 3, 5, 7, 9 };
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var i = binarySearch(i8, my_list, 3);
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try expect(i != null);
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try expect(i.? == 1);
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i = binarySearch(i8, my_list, -1);
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try expect(i == null);
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}
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