doukaku9_2.js

function half(price) {
    return (price % 20 === 0) ? price / 2 : (price + 10) / 2;
}

function calcPrice(price, person) {
    switch(true) {
        case person[1] === "p"  : return 0;
        case person[1] === "w"  : return calcPrice(half(price), person[0] + "n");
        case person    === "Cn" : return half(price);
        case person    === "In" : return half(price);
        default                 : return price;
    }
}

function solve(input) {
    var basePrice  = parseInt(input.split(":")[0]);
    var passengers = input.split(":")[1];

    var ap = (passengers.match(/A./g) || []).map(function(p) { return calcPrice(basePrice, p) });
    var cp = (passengers.match(/C./g) || []).map(function(p) { return calcPrice(basePrice, p) });
    var ip = (passengers.match(/I./g) || []).map(function(p) { return calcPrice(basePrice, p) });
    ip.sort(function(a, b) { return a - b });
    if(ap.length) {
        ip = ip.slice(0, -ap.length * 2);
    }
    return ap.concat(cp).concat(ip).reduce(function(a, b) { return a + b }).toString();
}


function test(input, expected) {
    var result = solve(input);
    if(result !== expected) {
        console.log("-------------\ninput = %s\n\nexpected = %s\nresult   = %s", input, expected, result);
    }
}


test("210:Cn,In,Iw,Ap,Iw"                                         , "170");
test("220:Cp,In"                                                  , "110");
test("230:Cw,In,Iw"                                               , "240");
test("240:In,An,In"                                               , "240");
test("250:In,In,Aw,In"                                            , "260");
test("260:In,In,In,In,Ap"                                         , "260");
test("270:In,An,In,In,Ip"                                         , "410");
test("280:Aw,In,Iw,In"                                            , "210");
test("200:An"                                                     , "200");
test("210:Iw"                                                     , "60");
test("220:Ap"                                                     , "0");
test("230:Cp"                                                     , "0");
test("240:Cw"                                                     , "60");
test("250:In"                                                     , "130");
test("260:Cn"                                                     , "130");
test("270:Ip"                                                     , "0");
test("280:Aw"                                                     , "140");
test("1480:In,An,In,In,In,Iw,Cp,Cw,In,Aw,In,In,Iw,Cn,Aw,Iw"       , "5920");
test("630:Aw,Cw,Iw,An,An"                                         , "1740");
test("340:Cn,Cn,Ip,Ap"                                            , "340");
test("240:Iw,Ap,In,Iw,Aw"                                         , "120");
test("800:Cw,An,Cn,Aw,Ap"                                         , "1800");
test("1210:An,Ip,In,Iw,An,Iw,Iw,An,Iw,Iw"                         , "3630");
test("530:An,Cw,Cw"                                               , "810");
test("170:Aw,Iw,Ip"                                               , "90");
test("150:In,Ip,Ip,Iw,In,Iw,Iw,In,An,Iw,Aw,Cw,Iw,Cw,An,Cp,Iw"     , "580");
test("420:Cn,Cw,Cp"                                               , "320");
test("690:Cw,In,An,Cp,Cn,In"                                      , "1220");
test("590:Iw,Iw,Cn,Iw,Aw,In,In,Ip,Iw,Ip,Aw"                       , "1200");
test("790:Cw,Cn,Cn"                                               , "1000");
test("1220:In,In,An,An,In,Iw,Iw,In,In,Ip,In,An,Iw"                , "4590");
test("570:Cw,Cn,Cp"                                               , "440");
test("310:Cn,Cw,An,An,Iw,Cp,Cw,Cn,Iw"                             , "1100");
test("910:Aw,In,Iw,Iw,Iw,Iw,Iw,An,Cw,In"                          , "2290");
test("460:Iw,Cw,Cw,Cn"                                            , "590");
test("240:Iw,Iw,In,Iw,In,In,Cn,In,An"                             , "780");
test("1240:In,In,In,Ap,In,Cw,Iw,Iw,Iw,Aw,Cw"                      , "2170");
test("1000:Iw,Ip,In,An,In,In,In,An,In,Iw,In,In,Iw,In,Iw,Iw,Iw,An" , "5500");
test("180:In,Aw,Ip,Iw,In,Aw,In,Iw,Iw,In"                          , "330");
test("440:In,Ip,Cp,Aw,Iw,In,An"                                   , "660");
test("1270:Ap,In,An,Ip,In,Ip,Ip"                                  , "1270");