Discussion on: Advent of Code 2019 Solution Megathread - Day 3: Crossed Wires

function crosswires()
{
    let pretext = document.getElementsByTagName('pre')[0].innerHTML;
    let wires = pretext.split('\n').filter(w => w !== '').map(w => w.split(','));
    let points = [[{x:0, y:0}],[{x:0, y:0}]];
    let crosspoints = {};

    let bestpoint = {x:Number.MAX_SAFE_INTEGER, y:Number.MAX_SAFE_INTEGER};

    for(let stepi = 0; stepi < wires[0].length; stepi++)
    {
    let wire0step = wires[0][stepi];
    let wire1step = wires[1][stepi];

    let wire0points = stepToPoints(points[0][points[0].length-1], wire0step);

    for(let p0 of wire0points)
    {
        if(p0.x in crosspoints)
        {
        if(p0.y in crosspoints[p0.x])
        {
            crosspoints[p0.x][p0.y][0] = true;
        }
        else
        {
            crosspoints[p0.x][p0.y] = {0:true, 1: false};
        }

        }
        else
        {
        let obj = {};
        obj[p0.y] = {0:true, 1:false};
        crosspoints[p0.x] = obj;
        }
    }

    points[0] = points[0].concat(wire0points);

    let wire1points = stepToPoints(points[1][points[1].length-1], wire1step);

    for(let p1 of wire1points)
    {
        if(p1.x in crosspoints)
        {
        if(p1.y in crosspoints[p1.x])
        {
            crosspoints[p1.x][p1.y][1] = true;
        }
        else
        {
            crosspoints[p1.x][p1.y] = {0: false, 1: true};
        }

        }
        else
        {
        let obj = {};
        obj[p1.y] = {0:false, 1:true};
        crosspoints[p1.x] = obj;
        }
    }

    points[1] = points[1].concat(wire1points);

    }

    for(let x in crosspoints)
    {
    for(let y in crosspoints[x])
    {
        if(crosspoints[x][y][0] && crosspoints[x][y][1])
        {
        if(Math.abs(x) + Math.abs(y) < Math.abs(bestpoint.x) + Math.abs(bestpoint.y))
        {
            bestpoint = {x:x, y:y};
        }
        }
    }
    }

    return bestpoint;
}


function crosswires2()
{
    let pretext = document.getElementsByTagName('pre')[0].innerHTML;
    let wires = pretext.split('\n').filter(w => w !== '').map(w => w.split(','));
    let points = [[{x:0, y:0}],[{x:0, y:0}]];
    let steps = [0, 0]
    let crosspoints = {};

    let beststeps = Number.MAX_SAFE_INTEGER;

    for(let stepi = 0; stepi < wires[0].length; stepi++)
    {
    let wire0step = wires[0][stepi];
    let wire1step = wires[1][stepi];

    let wire0points = stepToPoints(points[0][points[0].length-1], wire0step);

    for(let p0 of wire0points)
    {
        steps[0]++;
        if(p0.x in crosspoints)
        {
        if(p0.y in crosspoints[p0.x])
        {
            if(crosspoints[p0.x][p0.y][0] == -1)
            {
            crosspoints[p0.x][p0.y][0] = steps[0];
            }
        }
        else
        {
            crosspoints[p0.x][p0.y] = {0:steps[0], 1: -1};
        }

        }
        else
        {
        let obj = {};
        obj[p0.y] = {0:steps[0], 1:-1};
        crosspoints[p0.x] = obj;
        }
    }

    points[0] = points[0].concat(wire0points);

    let wire1points = stepToPoints(points[1][points[1].length-1], wire1step);

    for(let p1 of wire1points)
    {
        steps[1]++;
        if(p1.x in crosspoints)
        {
        if(p1.y in crosspoints[p1.x])
        {
            if(crosspoints[p1.x][p1.y][1] == -1)
            {
            crosspoints[p1.x][p1.y][1] = steps[1];
            }
        }
        else
        {
            crosspoints[p1.x][p1.y] = {0: -1, 1: steps[1]};
        }

        }
        else
        {
        let obj = {};
        obj[p1.y] = {0:-1, 1:steps[1]};
        crosspoints[p1.x] = obj;
        }
    }

    points[1] = points[1].concat(wire1points);

    }

    for(let x in crosspoints)
    {
    for(let y in crosspoints[x])
    {
        if(crosspoints[x][y][0] > -1 && crosspoints[x][y][1] > -1)
        {
        let steps = crosspoints[x][y][0] + crosspoints[x][y][1];
        if(steps < beststeps)
        {
            beststeps = steps;
        }
        }
    }
    }

    return beststeps;
}


function stepToPoints(curPoint, step)
{
    let dist = parseInt(step.slice(1));
    let points = [];
    for(let i = 1; i <= dist; i++)
    {
    let nextPoint = {x:curPoint.x, y:curPoint.y};
    switch(step[0])
    {
        case 'U':
        nextPoint.y += i;
        break;
        case 'D':
        nextPoint.y -= i;
        break;
        case 'L':
        nextPoint.x += i;
        break
        case 'R':
        nextPoint.x -= i;
        break;
    }
    points.push(nextPoint);
    }

    return points;
}