uva-539-枚举

题意：

给你一个无向图,找最长路.

俩份代码,感觉map[][]简单易懂啊

#include<stdio.h>
#include<iostream>
#include<sstream>
#include<queue>
#include<map>
#include<memory.h>
#include <math.h>
#include<time.h>
#include <stdlib.h>
#include <algorithm>
using namespace std;
#define N 26
int n, m;
int mp = -1;
struct Edge
{
    int num;
    int s;
    int e;
};

int nn[N][N];
int ni[N];
Edge edges[N];
int vis[N];
int dfs(int cn, int cur)
{
    for(int i = 0; i < ni[cn]; i++)
    {
        if(vis[nn[cn][i]])
            continue;
        Edge edge = edges[nn[cn][i]];
        int e = edge.e == cn ? edge.s : edge.e;
        vis[nn[cn][i]] = 1;
        dfs(e, cur + 1);
        vis[nn[cn][i]] = 0;
    }
    mp = mp < cur ? cur : mp;
    return cur;
}
int main(const int argc, char** argv)
{
    //freopen("d:\\1.txt", "r", stdin);
    while (cin >> n >> m && (n && m))
    {
        memset(vis, 0, sizeof(vis));
        memset(nn, 0, sizeof(nn));
        memset(ni, 0, sizeof(ni));
        for(int i = 0; i < m; i++)
        {
            Edge edge;
            edge.num = i;
            cin >> edge.s >> edge.e;
            edges[i] = edge;
            nn[edge.s][ni[edge.s]++] = i;
            nn[edge.e][ni[edge.e]++] = i;
        }
        for(int i = 0; i < n; i++)
        {
            dfs(i, 0);
        }
        cout << mp << endl;
        mp = 0;
    }
    return 0;
}

 

#include<stdio.h>
#include<iostream>
#include<sstream>
#include<queue>
#include<map>
#include<memory.h>
#include <math.h>
#include<time.h>
#include <stdlib.h>
#include <algorithm>
using namespace std;
#define N 30
int n, m;
int mp = -1;

int nn[N][N];
int dfs(int cn, int cur)
{
    for(int i = 0; i < n; i++)
    {
        if(nn[cn][i])
        {
            nn[cn][i]--;
            nn[i][cn]--;
            dfs(i, cur + 1);
            nn[cn][i]++;
            nn[i][cn]++;
        }

    }
    mp = mp < cur ? cur : mp;
    return cur;
}
int main(const int argc, char** argv)
{
    //freopen("d:\\1.txt", "r", stdin);
    while (cin >> n >> m )
    {
        if(n==0&&m==0)
            return 0;
        memset(nn, 0, sizeof(nn));
        mp = 0;
        int s, e;
        for(int i = 0; i < m; i++)
        {
            cin >> s >> e;
            nn[s][e]++;
            nn[e][s]++;
        }
        for(int i = 0; i < n; i++)
        {
            dfs(i, 0);
        }
        cout << mp << endl;
    }
    return 0;
}