Число мостов - Bridge number

package main
import "fmt"
//import "github.com/skorobogatov/input"

type vertex struct {
        x      int
    mark   string
    comp   int
    edge   []*vertex
    parent *vertex
}

func main() {
    var i, n, m, v, u, comp_dfs1, comp_dfs2, t_c int
    var VisitVertex2 func(v *vertex, component int)
    var VisitVertex1 func(v *vertex) int
    var queue [](*vertex)

    fmt.Scanf("%d\n", &n)
    fmt.Scanf("%d\n", &m)

    list := make([]vertex, n)

    for i < m {
        fmt.Scanf("%d %d\n", &u, &v)
        list[u].edge, list[v].edge = append(list[u].edge, &list[v]), append(list[v].edge, &list[u])
        i++
    }

    Enqueue := func(Q [](*vertex), vert *vertex) []*vertex { return append(Q, vert) }
    Dequeue := func(Q [](*vertex), num int) *vertex { return Q[num] }

    VisitVertex1 = func(v *vertex) {
        E_G := v.edge
        v.mark = "gray"
        queue = Enqueue(queue, v)
        for i, _ := range E_G {
            u := E_G[i]
            if u.mark == "white" {
                u.parent = v
                VisitVertex1(u)
            }
        }
        v.mark = "black"
    }

    VisitVertex2 = func(v *vertex, component int) {
        v.comp = component
        E_G := v.edge
        for i, _ := range E_G {
            u := E_G[i]
            if u.comp == -1 && u.parent != v { VisitVertex2(u, component) }
        }
    }
    V_G := list
//DFS1
    for i, _ := range V_G { V_G[i].mark = "white" }
    for i, _ := range V_G {
        v := V_G[i]
        if v.mark == "white" {
            VisitVertex1(&v)
            comp_dfs1++
        }
    }
//DFS2
    for i, _ := range V_G { V_G[i].comp = -1 }
    for i, _ := range queue {
        v := Dequeue(queue, i)
        if v.comp == -1 {
            VisitVertex2(v, comp_dfs2)
            comp_dfs2++
        }
    }
    fmt.Printf("comp=%d\n", comp_dfs2-comp_dfs1)
}