图的m着色问题-回溯法-深度搜索

#include <bits/stdc++.h>
using namespace std;
int m;
int pointnum;
int edgenum;
int sum = 0;
int Graph[100][100];
int x[100];
void InPut()
{
    int pos1, pos2;
    scanf("%d %d", &pointnum, &m);
    scanf("%d", &edgenum);
    memset(Graph, 0, sizeof(Graph));
    for(int i = 1; i <= edgenum; ++i)
    {
        scanf("%d %d", &pos1, &pos2);
        Graph[pos1][pos2] = Graph[pos2][pos1] = 1;
    }
}
bool IsOk(int i)
{
    for(int j = 1; j < i; ++j)
        if(Graph[i][j] == 1 && x[j] == x[i])
            return false;
    return true;
}
void BackTrack(int i)
{
    if(i > pointnum)
    {
        sum += 1;
        printf("方法 %d : ", sum);
        for(int j = 1; j <= pointnum; ++j)
        {
            printf("%d ", x[j]);
        }
        printf("\n");
        return;
    }
    else
    {
        for(int j = 1; j <= m; ++j)
        {
            x[i] = j;
            if(IsOk(i))
                BackTrack(i + 1);
            x[i] = 0;
        }
    }
}
void OutPut()
{
    printf("一共有 %d 中绘色方案", sum);
}
int main()
{
    InPut();
    BackTrack(1);
    OutPut();
}