各版本最短路算法简单温习

原创 于 2014-11-17 23:29:43 发布 · 402 阅读 · 1 ·
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http://acm.hdu.edu.cn/showproblem.php?pid=1874

Floyd:
//#pragma comment(linker, "/STACK:61400000,61400000")
#include <set>
#include <map>
#include <list>
#include <stack>
#include <queue>
#include <cmath>
#include <cstdio>
#include <vector>
#include <string>
#include <iomanip>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
using namespace std;

#define pi 3.1415926535897932385
#define LL64 __int64
#define LL long long
#define oo 2147483647
#define N 100000100
#define M 210
#define INF 1e9

int tu[M][M];

int main()
{
    int n, m;
    
    //freopen("data.in", "r", stdin);
    //freopen("data.out", "w", stdout);
    //int _case = 1;
    //scanf("%d", &t);
    //while (t--)
    //for (int _case = 1; _case <= t; _case++)
    while (~scanf("%d%d", &n, &m))
    {
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j < n; j++)
            {
                if (i == j) tu[i][j] = 0;
                else tu[i][j] = N;
            }
        }
        for (int i = 0; i < m; i++)
        {
            int a, b, c;
            scanf("%d%d%d", &a, &b, &c);
            if (tu[a][b] == N) tu[a][b] = tu[b][a] = c;
            else tu[a][b] = tu[b][a] = min(tu[a][b], c);
        }
        int s, t;
        scanf("%d%d", &s, &t);
        for (int k = 0; k < n; k++)
        {
            for (int i = 0; i < n; i++)
            {
                for (int j = 0; j < n; j++)
                {
                    tu[i][j] = min(tu[i][j], tu[i][k] + tu[k][j]);
                }
            }
        }
        printf("%d\n", tu[s][t] == N ? -1 : tu[s][t]);
    }
    
    return 0;
}
SPFA：
//#pragma comment(linker, "/STACK:61400000,61400000")
#include <set>
#include <map>
#include <list>
#include <stack>
#include <queue>
#include <cmath>
#include <cstdio>
#include <vector>
#include <string>
#include <iomanip>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
using namespace std;

#define pi 3.1415926535897932385
#define LL64 __int64
#define LL long long
#define oo 2147483647
#define N 100000100
#define M 210
#define INF 1e9

int tu[M][M];
int dis[M];
queue<int> q;

int main()
{
    int n, m;
    
    //freopen("data.in", "r", stdin);
    //freopen("data.out", "w", stdout);
    //int _case = 1;
    //scanf("%d", &t);
    //while (t--)
    //for (int _case = 1; _case <= t; _case++)
    while (~scanf("%d%d", &n, &m))
    {
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j < n; j++)
            {
                tu[i][j] = N;
            }
        }
        for (int i = 0; i < m; i++)
        {
            int a, b, c;
            scanf("%d%d%d", &a, &b, &c);
            if (tu[a][b] == N) tu[a][b] = tu[b][a] = c;
            else tu[a][b] = tu[b][a] = min(tu[a][b], c);
        }
        int s, t;
        scanf("%d%d", &s, &t);
        for (int i = 0; i < n; i++)
        {
            if (i == s) dis[i] = 0;
            else dis[i] = N;
        }
        while (!q.empty())
        {
            q.pop();
        }
        q.push(s);
        while (!q.empty())
        {
            int so = q.front();
            q.pop();
            for (int i = 0; i < n; i++)
            {
                if (i == so) continue;
                if (dis[i] > dis[so] + tu[so][i])
                {
                    dis[i] = dis[so] + tu[so][i];
                    q.push(i);
                }
            }
        }
        printf("%d\n", dis[t] == N ? -1 : dis[t]);
    }
    
    return 0;
}
传统Dijkstra：
//#pragma comment(linker, "/STACK:61400000,61400000")
#include <set>
#include <map>
#include <list>
#include <stack>
#include <queue>
#include <cmath>
#include <cstdio>
#include <vector>
#include <string>
#include <iomanip>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
using namespace std;

#define pi 3.1415926535897932385
#define LL64 __int64
#define LL long long
#define oo 2147483647
#define N 100000100
#define M 210
#define INF 1e9

int tu[M][M];
int dis[M];
bool tp[M];

int main()
{
    int n, m;
    
    //freopen("data.in", "r", stdin);
    //freopen("data.out", "w", stdout);
    //int _case = 1;
    //scanf("%d", &t);
    //while (t--)
    //for (int _case = 1; _case <= t; _case++)
    while (~scanf("%d%d", &n, &m))
    {
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j < n; j++)
            {
                tu[i][j] = oo;
            }
        }
        for (int i = 0; i < m; i++)
        {
            int a, b, c;
            scanf("%d%d%d", &a, &b, &c);
            if (tu[a][b] == oo) tu[a][b] = tu[b][a] = c;
            else tu[a][b] = tu[b][a] = min(tu[a][b], c);
        }
        int s, t;
        scanf("%d%d", &s, &t);
        for (int i = 0; i < n; i++)
        {
            if (i == s) dis[i] = 0;
            else dis[i] = oo;
        }
        memset(tp, 0, sizeof(tp));
        for (int i = 0; i < n; i++)
        {
            int p = -1;
            int d = oo;
            for (int j = 0; j < n; j++)
            {
                if (tp[j] == 0)
                {
                    if (d > dis[j])
                    {
                        d = dis[j];
                        p = j;
                    }
                }
            }
            if (p == -1) break;
            for (int j = 0; j < n; j++)
            {
                if (tu[p][j] != oo)
                {
                    dis[j] = min(dis[j], dis[p] + tu[p][j]);
                }
            }
            tp[p] = 1;
        }
        printf("%d\n", dis[t] == oo ? -1 : dis[t]);
    }
    
    return 0;
}
HeapDijkstra：
//#pragma comment(linker, "/STACK:61400000,61400000")
#include <set>
#include <map>
#include <list>
#include <stack>
#include <queue>
#include <cmath>
#include <cstdio>
#include <vector>
#include <string>
#include <iomanip>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
using namespace std;

#define pi 3.1415926535897932385
#define LL64 __int64
#define LL long long
#define oo 2147483647
#define N 100000100
#define M 210
#define INF 1e9

int tu[M][M];
int dis[M];

struct cmp
{
    bool operator () (int x, int y)
    {
        return dis[x] > dis[y];
    }
};

priority_queue<int, vector<int>, cmp> q;

int main()
{
    int n, m;
    
    //freopen("data.in", "r", stdin);
    //freopen("data.out", "w", stdout);
    //int _case = 1;
    //scanf("%d", &t);
    //while (t--)
    //for (int _case = 1; _case <= t; _case++)
    while (~scanf("%d%d", &n, &m))
    {
        memset(tu, -1, sizeof(tu));
        for (int i = 0; i < m; i++)
        {
            int a, b, c;
            scanf("%d%d%d", &a, &b, &c);
            if (tu[a][b] == -1) tu[a][b] = tu[b][a] = c;
            else tu[a][b] = tu[b][a] = min(tu[a][b], c);
        }
        int s, t;
        scanf("%d%d", &s, &t);
        for (int i = 0; i < n; i++)
        {
            if (i == s) dis[i] = 0;
            else dis[i] = oo;
        }
        while (!q.empty())
        {
            q.pop();
        }
        q.push(s);
        while (!q.empty())
        {
            int p = q.top();
            q.pop();
            for (int j = 0; j < n; j++)
            {
                if (tu[p][j] != -1)
                {
                    if (dis[j] > dis[p] + tu[p][j])
                    {
                        dis[j] = dis[p] + tu[p][j];
                        q.push(j);
                    }
                }
            }
        }
        printf("%d\n", dis[t] == oo ? -1 : dis[t]);
    }
    
    return 0;
}
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