PTA 1154 Vertex Coloring

题目链接：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 \(10^4\)), 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 1:

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

题意

给定一个图，以及每个顶点的颜色，问是否所有边连接的两个顶点颜色不同。

思路

枚举每一条边即可。

代码

#include <bits/stdc++.h>

using namespace std;

const int maxn = 1e4 + 10;

pair<int, int> edges[maxn];

int colors[maxn];

int main() {

    ios::sync_with_stdio(false);

    cin.tie(0);

    int n, m;

    cin >> n >> m;

    for(int i = 0; i < m; ++i) {

        int x, y;

        cin >> x >> y;

        edges[i] = {x, y};

    }

    int k;

    cin >> k;

    while(k--) {

        map<int, int> mp;

        for(int i = 0; i < n; ++i) {

            cin >> colors[i];

            mp[colors[i]]++;

        }

        int flag = 1;

        for(int i = 0; i < m; ++i) {

            int x = edges[i].first, y = edges[i].second;

            if(colors[x] == colors[y]) {

                flag = 0;

                break;

            }

        }

        if(flag) {

            cout << mp.size() << "-coloring" << endl;

        } else {

            cout << "No" << endl;

        }

    }

    return 0;

}

巴特西

PTA 1154 Vertex Coloring

Input Specification:

Output Specification:

Sample Input 1:

Sample Output:

题意

思路

代码

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