PAT_A1154#Vertex Coloring

Source:

PAT A 1154 Vertex Coloring (25 分)

Description:

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 1), 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

Keys:

• 图的存储和遍历
• set（C++ STL）
• 散列（Hash）

Attenrion:

• 矩阵存储图，规模小于10^3
• 对于多组测试用例的输入，要注意统计值和哈希函数的初始化（出题老师太坏了，测试用例即使不初始化也是对的-,-）

Code:

/*
Data: 2019-08-02 21:08:29
Problem: PAT_A1154#Vertex Coloring
AC: 17:39

题目大意：
判断图中相连的顶点是否共色
*/
#include<cstdio>
#include<set>
using namespace std;
const int M=1e4+10;
struct node
{
    int u,v;
}grap[M];
int color[M];

int main()
{
#ifdef ONLINE_JUDGE
#else
    freopen("Test.txt", "r", stdin);
#endif // ONLINE_JUDGE

    int n,m,k;
    scanf("%d%d", &m,&n);
    for(int i=0; i<n; i++)
        scanf("%d%d", &grap[i].u,&grap[i].v);
    scanf("%d", &k);
    while(k--)
    {
        set<int> mp;
        for(int i=0; i<m; i++)
        {
            scanf("%d", &color[i]);
            mp.insert(color[i]);
        }
        for(int i=0; i<n; i++)
        {
            if(color[grap[i].u] == color[grap[i].v])
            {
                mp.clear();
                break;
            }
        }
        if(mp.size())
            printf("%d-coloring\n", mp.size());
        else
            printf("No\n");
    }

    return 0;
}