Cod sursa(job #1261626)

Utilizator andreiiiiPopa Andrei andreiiii Data 12 noiembrie 2014 16:29:54
Problema Nowhere-zero Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 4.17 kb
#include <algorithm>
#include <bitset>
#include <cstdio>
#include <cassert>
#include <cmath>
#include <vector>

using namespace std;

const int Nmax = 100005, Mmax = Nmax * 3;

struct Point {
    double x, y;
};

Point points[Nmax];
pair<int, int> edges[Mmax], Pos[Mmax];
int Capacity[Mmax];

vector<int> G[Nmax], Gz[Mmax];
int Zone[Mmax][2], Color[Mmax];

int deg[Mmax];
bitset<Mmax> used;

int getZones(int N, int M) {
    int czones = 0;
    for (int i = 1; i <= N; ++i) {
        sort(G[i].begin(), G[i].end(), [i](const int a, const int b) {
            int node1 = edges[a].first ^ edges[a].second ^ i;
            int node2 = edges[b].first ^ edges[b].second ^ i;
            return atan2(points[node1].y - points[i].y, points[node1].x - points[i].x) < atan2(points[node2].y - points[i].y, points[node2].x - points[i].x);
        });
        for (int j = 0; j < int(G[i].size()); ++j) {
            int p = G[i][j];
            (i == edges[p].first ? Pos[p].first: Pos[p].second) = j;
        }
    }

    for (int i = 1; i <= M; ++i) {
        for (int j = 0; j < 2; ++j) {
            if (Zone[i][j]) continue;

            czones++;
            int goodSign = j == 0 ? -1: 1;
            for (int k = i, lastNode = edges[i].second, lastOther = edges[i].first; ;) {
                if (Zone[k][lastNode == edges[k].second ? j: (j ^ 1)]) break;

                Zone[k][lastNode == edges[k].second ? j: (j ^ 1)] = czones;
                int goodEdge = G[lastNode][((lastNode == edges[k].second ? Pos[k].second: Pos[k].first) + goodSign + G[lastNode].size()) % G[lastNode].size()];

                int node = lastNode ^ edges[goodEdge].second ^ edges[goodEdge].first;
                int other = edges[goodEdge].first ^ edges[goodEdge].second ^ node;

                k = goodEdge;
                lastNode = node;
                lastOther = other;
            }
        }
    }

    //assert(czones == 2 + M - N);
    return czones;
}

void buildZoneGraph(int N, int M, int czones) {
    for (int i = 1; i <= M; ++i) {
        Gz[Zone[i][0]].push_back(Zone[i][1]);
        Gz[Zone[i][1]].push_back(Zone[i][0]);
    }
    for (int i = 1; i <= czones; ++i) {
        sort(Gz[i].begin(), Gz[i].end());
        Gz[i].erase(unique(Gz[i].begin(), Gz[i].end()), Gz[i].end());
    }
}

void colorNewGraph(int N) {
    vector<int> order;
    order.reserve(N);
    for (int i = 1; i <= N; ++i) {
        deg[i] = Gz[i].size();
        if (deg[i] < 6) {
            order.push_back(i);
            used[i] = 1;
        }
    }

    for (int i = 0; i < N; ++i) {
        int node = order[i];

        for (int p: Gz[node]) {
            deg[p]--;
            if (!used[p] && deg[p] < 6) {
                used[p] = 1;
                order.push_back(p);
            }
        }
    }
    reverse(order.begin(), order.end());

    for (int node: order) {
        bool usedCol[7];
        for (int i = 0; i < 7; ++i) usedCol[i] = 0;
        for (int p: Gz[node])
            usedCol[Color[p]] = 1;

        for (int i = 1; ; ++i) {
            if (!usedCol[i]) {
                Color[node] = i;
                break;
            }
        }
    }
}

void setEdges(int N, int M) {
    for (int i = 1; i <= M; ++i) {
        Capacity[i] = Color[Zone[i][1]] - Color[Zone[i][0]];
        if (Capacity[i] < 0) {
            Capacity[i] = -Capacity[i];
            swap(edges[i].first, edges[i].second);
        }
    }
}

void writeAnswer(int N, int M) {
    for (int i = 1; i <= M; ++i)
        printf("%d %d %d\n", edges[i].first, edges[i].second, Capacity[i]);
}

int main()
{
    freopen("nowhere-zero.in", "r", stdin);
    freopen("nowhere-zero.out", "w", stdout);

    int N, M;
    scanf("%d%d", &N, &M);

    for (int i = 1; i <= N; ++i)
        scanf("%lf%lf", &points[i].x, &points[i].y);

    for (int i = 1; i <= M; ++i) {
        scanf("%d%d", &edges[i].first, &edges[i].second);
        G[edges[i].first].push_back(i);
        G[edges[i].second].push_back(i);
    }

    int czones = getZones(N, M);
    buildZoneGraph(N, M, czones);
    colorNewGraph(czones);
    setEdges(N, M);
    writeAnswer(N, M);
}