stpetersburg.js

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
/**
 * St. Petersburg paradox
 * by Kazuki Maeda
 * Last-Modified: Jul. 24, 2019
 */

var mode = ''
var numflip = 0;
var thread;
var prize = 0;
var numendless = 0;
var stat;
var fliptext;

window.onload = function(){
    document.getElementById('flip').addEventListener('click', flip, true);
    document.getElementById('challenges').addEventListener('click', challenges, true);
    document.getElementById('endless').addEventListener('click', endless, true);
}

function flip(){
    if(mode != 'flip'){
        if(mode != 'flipcontinue'){
            historytext = '';
        }

        document.getElementById('result').innerHTML = '';
        mode = 'flip';
        numflip = 0;
        fliptext = '';
    }
    var r = Math.floor(Math.random()*2);
    var addhistoryflag = false;
    var rchar;
    if(r){
        fliptext += '○ ';
        ++numflip;
    } else {
        fliptext += '×：' + Math.pow(2, numflip) + '円獲得！！';
        addhistoryflag = true;
        mode = 'flipcontinue';
    }
    document.getElementById('result').innerHTML
        = fliptext + '<hr><em>履歴：</em><br>' + historytext;
    if(addhistoryflag)
        historytext = fliptext + '<br>' + historytext;
}

function addstat(stat, n){
    if(typeof stat[n] === 'undefined')
        stat[n] = 1;
    else
        ++stat[n];
}

function challenges(){
    mode = 'challenges';
    var numchallenges = Math.floor(document.getElementById('numchallenges').value);
    prize = 0;
    var restext = '';
    var stat = [];
    document.getElementById('result').innerHTML = '';
    for(var k = 0; k < numchallenges; ++k){
        numflip = 0;
        while(1){
            var r = Math.floor(Math.random()*2);
            var rchar;
            if(r){
                restext += '○ ';
                ++numflip;
            } else {
                addstat(stat, numflip);
                var t = Math.pow(2, numflip);
                restext += '×：' + t + '円獲得！！<br>';
                prize += t;
            }
            if(!r)
                break;
        }
    }
    document.getElementById('result').innerHTML =
        numchallenges.toFixed() + '回挑戦した結果，合計獲得金額：' + prize.toFixed() + '円！！ 1回の平均獲得金額：' + (prize/numchallenges) + '円！！<hr>';
    for(var k = 0; k < stat.length; ++k){
        document.getElementById('result').innerHTML += '2<sup>' + k + '</sup>=' + Math.pow(2, k) +  '円獲得回数：';
        var t;
        if(typeof stat[k] === 'undefined')
            t = 0;
        else
            t = stat[k];
        document.getElementById('result').innerHTML += t + '回（' + (t/numchallenges*100) + '%）<br>';
    }
    document.getElementById('result').innerHTML += '<hr><em>履歴：</em><br>';
    document.getElementById('result').innerHTML += restext;
}

function endless(){
    if(mode != 'endless'){
        if(mode != 'inendless'){
            prize = 0;
            numendless = 0;
            stat = [];
        }
        mode = 'endless';
        thread = setInterval("endlessupdate();", 1000/60);
        document.getElementById('flip').disabled = true;
        document.getElementById('challenges').disabled = true;
        document.getElementById('endless').value = 'もう飽きた';
    } else {
        mode = 'inendless';
        document.getElementById('flip').disabled = false;
        document.getElementById('challenges').disabled = false;
        document.getElementById('endless').value = '飽きるまで挑戦し続ける';
        clearInterval(thread);
    }
}

function endlessupdate(){
    var speed = Math.floor(document.getElementById('speed').value);
    speed = speed <= 0 ? 1 : speed;
    for(var k = 0; k < speed; ++k){
        ++numendless;
        numflip = 0;
        while(1){
            var r = Math.floor(Math.random()*2);
            if(r){
                ++numflip;
            } else {
                addstat(stat, numflip);
                prize += Math.pow(2, numflip);
            }
            if(!r)
                break;
        }
    }

    document.getElementById('result').innerHTML
        = numendless.toFixed() + '回挑戦した結果，合計獲得金額：' + prize.toFixed() + '円！！ 1回の平均獲得金額：' + (prize/numendless).toFixed(16) + '円！！<hr>';
    for(var k = 0; k < stat.length; ++k){
        document.getElementById('result').innerHTML += '2<sup>' + k + '</sup>=' + Math.pow(2, k) + '円獲得回数：';
        var t;
        if(typeof stat[k] === 'undefined')
            t = 0;
        else
            t = stat[k];
        document.getElementById('result').innerHTML += t + '回（' + (t/numendless*100).toFixed(16) + '%）<br>';
    }
}