PAT 甲级 1154 Vertex Coloring

https://pintia.cn/problem-sets/994805342720868352/problems/1071785301894295552

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

代码：

#include <bits/stdc++.h>
using namespace std;

const int maxn = 1e4 + 10;
int N ,M, K;
vector<int> v[maxn];
map<int, int> mp;

int main() {
    scanf("%d%d", &N, &M);
    while(M --) {
        int a, b;
        scanf("%d%d", &a, &b);
        v[a].push_back(b);
        v[b].push_back(a);
    }

    scanf("%d", &K);
    while(K --) {
        mp.clear();
        set<int> s;
        s.clear();
        for(int i = 0; i < N; i ++) {
            int x;
            scanf("%d", &x);
            s.insert(x);
            mp[i] = x;
        }

        bool flag = true;
        for(int i = 0; i < N; i ++) {
            for(int j = 0; j < v[i].size(); j ++) {
                if(mp[i] == mp[v[i][j]]) {
                    flag = false;
                    break;
                }
            }
            if(flag) continue;
            else break;
        }

        if(!flag) printf("No\n");
        else printf("%d-coloring\n", (int)s.size());
    }
    return 0;
}　　

　　今天第一题打卡 简单图论

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