PAT : PAT (Advanced Level) Practice 1154 Vertex Coloring

A proper vertex coloring is a labeling of the graph's vertices with colors such that no two vertices sharing the same edge have the same color. A coloring using at most k colors is called a (proper) k-coloring.

Now you are supposed to tell if a given coloring is a proper k-coloring.

Input Specification:

Each input file contains one test case. For each case, the first line gives two positive integers N and M (both no more than 104), being the total numbers of vertices and edges, respectively. Then M lines follow, each describes an edge by giving the indices (from 0 to N−1) of the two ends of the edge.

After the graph, a positive integer K (≤ 100) is given, which is the number of colorings you are supposed to check. Then K lines follow, each contains N colors which are represented by non-negative integers in the range of int. The i-th color is the color of the i-th vertex.

Output Specification:

For each coloring, print in a line k-coloring if it is a proper k-coloring for some positive k, or No if not.

Sample Input:

10 11
8 7
6 8
4 5
8 4
8 1
1 2
1 4
9 8
9 1
1 0
2 4
4
0 1 0 1 4 1 0 1 3 0
0 1 0 1 4 1 0 1 0 0
8 1 0 1 4 1 0 5 3 0
1 2 3 4 5 6 7 8 8 9

Sample Output:

4-coloring
No
6-coloring
No

#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <cstring>
#include <map>
#include <set>
using namespace std;
int getdigit(void)
{
    int temp{0};
    char ch;
    while (1)
    {
        ch = getchar();
        if (ch == ' ' || ch == '\n' || ch == EOF)
            return temp;
        temp = temp * 10 + ch - '0';
    }
}
int main(int argc, char *argv[])
{
    int vertice{getdigit()}, edge{getdigit()};
    vector<vector<int>> Vec(vertice);
    while (edge--)
    {
        int a{getdigit()}, b{getdigit()};
        Vec[a].push_back(b);
        Vec[b].push_back(a);
    }
    edge = getdigit();
    while (edge--)
    {
        vector<vector<int>> book(vertice);
        set<int> Map;
        int temp;
        bool isok = true;
        for (int i = 0; i < vertice; ++i)
        {
            temp = getdigit();
            if (isok)
            {
                if (book[i].empty())
                    book[i].push_back(temp);
                else
                {
                    for (const auto &k : book[i])
                    {
                        if (k == temp)
                        {
                            isok = false;
                            break;
                        }
                    }
                    if (!isok)
                        continue;
                }
                Map.insert(temp);
                for (const auto &k : Vec[i])
                    if (k > i)
                        book[k].push_back(temp);
            }
        }
        if (isok)
            printf("%lu-coloring\n", Map.size());
        else
            printf("No\n");
    }
    return EXIT_SUCCESS;
}

充分利用STL的强大容器～

vector建立邻接表存储图；

>> 识别每个节点的记录颜色是否与当前节点颜色相同

>> set : 更新颜色个数

>> 遍历临界表，在比自己节点号大的节点下记录自己的颜色，以供第一步比对

输出 Map.size()

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