const std = @import("std");
const print = std.debug.print;
const expect = std.testing.expect;

test "simple partition #1" {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    const allocator = gpa.allocator();
    defer {
        _ = gpa.deinit();
    }

    const arr = try allocator.alloc(u64, 3);
    arr[0] = 1;
    arr[1] = 3;
    arr[2] = 5;
    defer {
        allocator.free(arr);
    }
    const res = bipartition(arr, 0, @as(u64, arr.len - 1), 2);
    // std.log.warn("Res {}", .{res});
    try expect(res == 1);
}

test "simple partition #2" {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    const allocator = gpa.allocator();
    defer {
        _ = gpa.deinit();
    }

    const arr = try allocator.alloc(u64, 4);
    arr[0] = 1;
    arr[1] = 3;
    arr[2] = 5;
    arr[3] = 6;
    defer {
        allocator.free(arr);
    }
    const res = bipartition(arr, 0, @as(u64, arr.len - 1), 4);
    // std.log.warn("Res {}", .{res});
    try expect(res == 2);
}

test "simple partition #3" {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    const allocator = gpa.allocator();
    defer {
        _ = gpa.deinit();
    }

    const arr = try allocator.alloc(u64, 4);
    arr[0] = 1;
    arr[1] = 3;
    arr[2] = 5;
    arr[3] = 6;
    defer {
        allocator.free(arr);
    }
    const res = bipartition(arr, 0, @as(u64, arr.len - 1), 0);
    // std.log.warn("Res {}", .{res});
    try expect(res == 0);
}

test "simple partition #4" {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    const allocator = gpa.allocator();
    defer {
        _ = gpa.deinit();
    }

    const arr = try allocator.alloc(u64, 4);
    arr[0] = 1;
    arr[1] = 3;
    arr[2] = 5;
    arr[3] = 6;
    defer {
        allocator.free(arr);
    }
    const res = bipartition(arr, 0, @as(u64, arr.len - 1), 7);
    // std.log.warn("Res {}", .{res});
    try expect(res == 4);
}

test "simple partition #5" {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    const allocator = gpa.allocator();
    defer {
        _ = gpa.deinit();
    }

    const arr = try allocator.alloc(u64, 4);
    arr[0] = 1;
    arr[1] = 3;
    arr[2] = 5;
    arr[3] = 6;
    defer {
        allocator.free(arr);
    }
    const res = bipartition(arr, 0, @as(u64, arr.len - 1), 6);
    // std.log.warn("Res {}", .{res});
    try expect(res == 3);
}

pub fn bipartition(arr: []u64, t1: u64, t2: u64, v: u64) u64 {
    // std.log.warn("Arr called with {}, {}, {}", .{ t1, t2, v });
    var x1: u64 = t1;
    var x2: u64 = t2;
    var x: u64 = undefined;

    if (arr.len <= 0) {
        return x1;
    }

    if (v < arr[x1]) {
        return x1;
    }

    if (v > arr[t2]) {
        return t2 + 1;
    }

    while (x1 < x2 - 1) {
        // std.log.warn("Round {},{}", .{ t1, t2 });
        x = (x1 + x2) / 2;
        if (arr[x] < v) {
            x1 = x;
        } else {
            x2 = x;
        }
    }

    return x2;
}

pub fn main() !void {
    print("Hello World {}!!!\n", .{1});
}