javascript实现prim算法

<script type="text/javascript">
    //图的构建
    function vnode() {
        this.visited = 0;
        this.vertex = 0;
        this.arcs = new Array();
    }
    function G() {
        this.adjlist = new Array();
    }
    //0  1  2  3  4  5
    var a = [[0, 7, 8, 0, 0, 9], //
             [0, 0, 0, 2, 5, 0], //
             [0, 0, 0, 5, 0, 6], //
             [0, 0, 0, 0, 9, 0], //
             [0, 0, 0, 0, 0, 7], //
             [0, 0, 0, 0, 0, 0]]; //
    function creategraph() {
        var g = new G();
        for (i = 0; i < 6; i++) {
            g.adjlist[i] = new vnode();
            g.adjlist[i].vertex = i;
            g.adjlist[i].arcs = (function () {
                var b = new Array();
                for (j = 0; j < 6; j++)
                    if (a[i][j]) { b.push(new Number(j)); b[b.length - 1].weight = a[i][j]; }
                return b;
            })();
        }
        return g;
    }
    var s = new Array();
    var arcs = new Array();
    var e = new Array();
    var g = creategraph();
    for (i = 0; i < 6; i++) {
        for (j = 0; j < g.adjlist[i].arcs.length; j++) {
            var b = {};
            b.a = i;
            b.b = g.adjlist[i].arcs[j];
            b.c = g.adjlist[i].arcs[j].weight;
            arcs.push(b);
        }

    }
    arcs.sort(function (a, b) {
        return a.c - b.c;
    })
    //for(i=0;i<arcs.length;i++)alert(arcs[i].a+"---"+arcs[i].b);
    s.push(g.adjlist[0]);
    var flag = 0; var flag1 = 0;
    alert(s.length + "---" + g.adjlist.length);
    while (s.length < g.adjlist.length) {
        flag1 = 0;
        for (i = 0; i < arcs.length; i++) {
            flag = 0;
            if (flag1) break;
            for (j = 0; j < s.length; j++) {
                if (flag) break;
                if (arcs[i].a == s[j].vertex)
                    for (k = 0; k < s.length; k++) {
                        if (arcs[i].b == s[k].vertex) { flag = 1; break; }
                        if (k == (s.length - 1)) {
                            alert(arcs[i].a + "---" + arcs[i].b);
                            s.push(g.adjlist[arcs[i].b]);
                            e.push(arcs[i]); arcs.splice(i, 1);
                            flag1 = 1;
                            flag = 1;
                            break;
                        }
                    }
                else if (arcs[i].b == s[j].vertex)
                    for (k = 0; k < s.length; k++) {
                        if (arcs[i].a == s[k].vertex) { flag = 1; break; }
                        if (k == (s.length - 1)) {
                            alert(arcs[i].a + "---" + arcs[i].b);
                            s.push(g.adjlist[arcs[i].a]);
                            e.push(arcs[i]); arcs.splice(i, 1);
                            flag1 = 1;
                            flag = 1;
                            break;
                        }
                    }
            }

        }
    }
</script>