4541: [Hnoi2016]矿区

Posted 2020-08-22 AωD!

学习了一下平面图剖分的姿势，orz cbh

每次只要随便选择一条边，然后不停尽量向左转就行

#include <bits/stdc++.h>
#define N 1300000
#define M 5000013
#define LL long long
#define pb push_back
using namespace std;
LL n, m, k;
struct point 
{
    LL x, y;
} S[N];
vector <LL> bi[N];
vector <LL> re[N], vis[N], s1[N], s2[N];
vector <LL> bt[N], ca[N], cb[N];
LL tot_are;
LL siz[N], sum1[N], sum2[N], tot[N];
LL nwc;
LL comp(LL a, LL b)
{
    return atan2(S[a].y - S[nwc].y, S[a].x - S[nwc].x) > atan2(S[b].y - S[nwc].y, S[b].x - S[nwc].x);
}
LL getsiz(point a, point b, point c)
{
    return (b.x - a.x) * (c.y - a.y) - (c.x - a.x) * (b.y - a.y);
}
  
namespace addr
{
    LL hs[M]; LL dt[M];
    LL get(LL a, LL b)
    {
        return 1ll * a * 1000000 + b;
    }
    LL & find(LL a, LL b)
    {
        LL p = get(a, b); LL q = p % M;
        while (hs[q] && hs[q] != p) q = (q + 1) % M;
        hs[q] = p; return dt[q];
    }
}
LL tvis[N], fa[N];
void dfs(LL t)
{
    //cout << t << "\\n";
     
    tvis[t] = 1;
    sum1[t] = siz[t] * siz[t];
    sum2[t] = siz[t] * 2;
    for (LL i = 0; i < bt[t].size(); ++ i)
        if (!tvis[bt[t][i]])
        {
            dfs(bt[t][i]); fa[bt[t][i]] = t;
            sum1[t] += sum1[bt[t][i]];
            sum2[t] += sum2[bt[t][i]];
            s1[ca[t][i]][addr :: find(ca[t][i], cb[t][i])] = sum1[bt[t][i]];
            s2[ca[t][i]][addr :: find(ca[t][i], cb[t][i])] = sum2[bt[t][i]];
            s1[cb[t][i]][addr :: find(cb[t][i], ca[t][i])] = -sum1[bt[t][i]];
            s2[cb[t][i]][addr :: find(cb[t][i], ca[t][i])] = -sum2[bt[t][i]];
        }
}
LL read()
{
    LL x=0,f=1;char ch=getchar();
    while(ch<\'0\'||ch>\'9\'){if(ch==\'-\')f=-1;ch=getchar();}
    while(ch>=\'0\'&&ch<=\'9\'){x=x*10+ch-\'0\';ch=getchar();}
    return x*f;
}
LL c = 0;
int main()
{
    //freopen("mine2.in", "r", stdin);
    n = read(); m = read(); k = read();
    for (LL i = 1; i <= n; ++ i) S[i].x = read(), S[i].y = read();
    for (LL i = 1; i <= m; ++ i)
    {
        LL a, b;
        a = read(); b = read();
        bi[a].push_back(b);
        bi[b].push_back(a);
    }
    for (LL i = 1; i <= n; ++ i) re[i].resize(bi[i].size()), s1[i] = s2[i] = vis[i] = re[i];
    for (LL i = 1; i <= n; ++ i) nwc = i, sort(bi[i].begin(), bi[i].end(), comp);
    for (LL i = 1; i <= n; ++ i)
        for (LL j = 0; j < bi[i].size(); ++ j)
            addr :: find(i, bi[i][j]) = j;
    for (LL i = 1; i <= n; ++ i)
        for (LL j = 0; j < bi[i].size(); ++ j)
            re[i][j] = addr :: find(bi[i][j], i);
          
    for (LL i = 1; i <= n; ++ i)
        for (LL j = 0; j < bi[i].size(); ++ j)
            if (!vis[i][j])
            {
                tot_are ++;
                for (LL k = i, p = j; !vis[k][p]; )
                {
                    siz[tot_are] += getsiz(S[i], S[k], S[bi[k][p]]);
                    vis[k][p] = tot_are;
                    LL np = (re[k][p] + 1) % bi[bi[k][p]].size();
                    k = bi[k][p];
                    p = np;
                }
                if (siz[tot_are] < 0) c = tot_are;
            }
    for (LL i = 1; i <= n; ++ i)
        for (LL j = 0; j < bi[i].size(); ++ j)
            bt[vis[i][j]].push_back(vis[bi[i][j]][re[i][j]]),
            ca[vis[i][j]].push_back(i),
            cb[vis[i][j]].push_back(bi[i][j]);
    dfs(c);
    for (LL i = 1, last = 0; i <= k; ++ i)
    {
        LL d, ns1 = 0, ns2 = 0;
        d = read(); d = (d + last) % n + 1;
        LL fs, ls, nw;
        fs = read(); fs = (fs + last) % n + 1; ls = fs;
        for (LL j = 2; j <= d; ++ j, ls = nw)
        {
            nw = read(); nw = (nw + last) % n + 1;
            ns1 += s1[ls][addr :: find(ls, nw)];
            ns2 += s2[ls][addr :: find(ls, nw)];
        }
        ns1 += s1[ls][addr :: find(ls, fs)];
        ns2 += s2[ls][addr :: find(ls, fs)];
        LL g = __gcd(ns1, ns2);
        cout << ns1 / g << " " << ns2 / g << "\\n";
        last = ns1 / g;
    }
}

 

放在class里的东西还会爆栈QAQ，以后不敢用了