2023-02-14：魔物了占领若干据点，这些据点被若干条道路相连接， roads[i] = [x, y] 表示编号 x、y 的两个据点通过一条道路连接。 现在勇者要将按照以下原则将这些据点逐一夺回：

use std::iter::repeat;fn main() {    let cost = vec![1, 2, 3, 4, 5, 6];    let roads = vec![        vec![0, 1],        vec![0, 2],        vec![1, 3],        vec![2, 3],        vec![1, 2],        vec![2, 4],        vec![2, 5],    ];    let ans = unsafe { Solution::minimum_cost(cost, roads) };    println!("ans = {:?}", ans);}
struct Solution {}
impl Solution {    pub fn minimum_cost(cost: Vec<i32>, roads: Vec<Vec<i32>>) -> i64 {        let mut roads = roads;        let n = cost.len() as i32;        if n == 1 {            return cost[0] as i64;        }        let m = roads.len() as i32;        let mut dc = DoubleConnectedComponents::new(n, m, &mut roads);        let mut ans: i64 = 0;        // dcc {a,b,c} {c,d,e}        if dc.dcc.len() == 1 {            ans = i64::MAX;            for num in cost.iter() {                ans = get_min(ans, *num as i64);            }        } else {            // 不只一个点双连通分量            let mut arr: Vec<i32> = vec![];            for set in dc.dcc.iter() {                let mut cutCnt = 0;                let mut curCost = i32::MAX;                for nodes in set.iter() {                    if dc.cut[*nodes as usize] {                        cutCnt += 1;                    } else {                        curCost = get_min(curCost, cost[*nodes as usize]);                    }                }                if cutCnt == 1 {                    arr.push(curCost);                }            }            arr.sort_by(|a, b| a.partial_cmp(b).unwrap());            for i in 0..arr.len() as i32 - 1 {                ans += arr[i as usize] as i64;            }        }        return ans;    }}
fn get_min<T: Clone + Copy + std::cmp::PartialOrd>(a: T, b: T) -> T {    if a < b {        a    } else {        b    }}
struct DoubleConnectedComponents {    // 链式前向星建图    head: Vec<i32>,    next: Vec<i32>,    to: Vec<i32>,
    dfn: Vec<i32>,    low: Vec<i32>,    stack: Vec<i32>,    dcc: Vec<Vec<i32>>,    cut: Vec<bool>,    edgeCnt: i32,    dfnCnt: i32,    top: i32,    root: i32,}impl DoubleConnectedComponents {    pub fn new(n: i32, m: i32, roads: &mut Vec<Vec<i32>>) -> Self {        let mut ans = DoubleConnectedComponents {            head: vec![],            next: vec![],            to: vec![],
            dfn: vec![],            low: vec![],            stack: vec![],            dcc: vec![],            cut: vec![],            edgeCnt: 0,            dfnCnt: 0,            top: 0,            root: 0,        };        ans.init(n, m);        ans.createGraph(roads);        ans.creatDcc(n);        ans    }
    fn init(&mut self, n: i32, m: i32) {        let t = repeat(-1).take(n as usize).collect::<Vec<i32>>();        self.head = t;        let t = repeat(0).take((m << 1) as usize).collect::<Vec<i32>>();        self.next = t;        let t = repeat(0).take((m << 1) as usize).collect::<Vec<i32>>();        self.to = t;        let t = repeat(0).take(n as usize).collect::<Vec<i32>>();        self.dfn = t;        let t = repeat(0).take(n as usize).collect::<Vec<i32>>();        self.low = t;        let t = repeat(0).take(n as usize).collect::<Vec<i32>>();        self.stack = t;        let t = repeat(false).take(n as usize).collect::<Vec<bool>>();        self.cut = t;        self.edgeCnt = 0;        self.dfnCnt = 0;        self.top = 0;        self.root = 0;    }
    fn createGraph(&mut self, roads: &mut Vec<Vec<i32>>) {        for edges in roads.iter() {            self.add(edges[0], edges[1]);            self.add(edges[1], edges[0]);        }    }
    fn add(&mut self, u: i32, v: i32) {        self.to[self.edgeCnt as usize] = v;        self.next[self.edgeCnt as usize] = self.head[u as usize];        self.head[u as usize] = self.edgeCnt;        self.edgeCnt += 1;    }
    fn creatDcc(&mut self, n: i32) {        for i in 0..n {            // 0 1 2 3 n-1            if self.dfn[i as usize] == 0 {                self.root = i;                self.tarjan(i);            }        }    }
    fn tarjan(&mut self, x: i32) {        self.dfnCnt += 1;        self.low[x as usize] = self.dfnCnt;        self.dfn[x as usize] = self.low[x as usize];        self.stack[self.top as usize] = x;        self.top += 1;        let mut flag = 0;        if x == self.root && self.head[x as usize] == -1 {            self.dcc.push(vec![]);            let t = (self.dcc.len() as i32 - 1) as usize;            self.dcc[t].push(x);        } else {            // 当前来到的节点是x            // x {a,b,c}            let mut i = self.head[x as usize];            while i >= 0 {                // y是下级节点                let mut y = self.to[i as usize];                if self.dfn[y as usize] == 0 {                    // y点没遍历过！                    self.tarjan(y);                    if self.low[y as usize] >= self.dfn[x as usize] {                        // 正在扎口袋                        flag += 1;                        if x != self.root || flag > 1 {                            self.cut[x as usize] = true;                        }                        let mut curAns: Vec<i32> = vec![];                        // 从栈里一次弹出节点                        // 弹到y停！                        // 弹出的节点都加入集合，x也加入，x不弹出                        self.top -= 1;                        let mut z = self.stack[self.top as usize];                        while z != y {                            curAns.push(z);                            self.top -= 1;                            z = self.stack[self.top as usize];                        }                        curAns.push(y);                        curAns.push(x);                        self.dcc.push(curAns);                    }                    self.low[x as usize] = get_min(self.low[x as usize], self.low[y as usize]);                } else {                    // y点已经遍历过了！                    self.low[x as usize] = get_min(self.low[x as usize], self.dfn[y as usize]);                }                i = self.next[i as usize];            }        }    }}