UVa 10801 - Lift Hopping (Floyd, Dijkstra, SPFA三合一）

#include <bits/stdc++.h>
using namespace std;
#define LL long long
const int MAXN = 100;
const int INF = 0x3f3f3f3f;
 
typedef pair<int, int> pii;
priority_queue<pii, vector<pii>, greater<pii> >q;
int mp[MAXN][MAXN], d[MAXN];
 
void Floyd()
{
    for (int k = 0; k < MAXN; k++)
        for (int i = 0; i < MAXN; i++)
            for (int j = 0; j < MAXN; j++)
                mp[i][j] = min(mp[i][j], mp[i][k] + mp[k][j] + 60);
}
 
void Dijkstra(int start)
{
    int i, j;
    for (i = 0; i < MAXN; i++)
        d[i] = INF;
    d[start] = 0;
    q.push(make_pair(d[start], start));
    while (!q.empty())
    {
        pii t = q.top();
        q.pop();
        int u = t.second;
        if (t.first != d[u])
            continue;
        for (int v = 0; v < MAXN; v++)
            if (u == 0)
            {
                if (d[v] > d[u] + mp[u][v])
                {
                    d[v] = d[u] + mp[u][v];
                    q.push(make_pair(d[v], v));
                }
            }
            else
                if (d[v] > d[u] + mp[u][v] + 60)
                {
                    d[v] = d[u] + mp[u][v] + 60;
                    q.push(make_pair(d[v], v));
                }
    }
}
 
void SPFA(int start)
{
    int vis[MAXN];
    queue<int> q;
    memset(vis, 0, sizeof vis);
    for (int i = 0; i < MAXN; i++)
        d[i] = INF;
    d[start] = 0;
    q.push(start);
    while (!q.empty())
    {
        int u = q.front();
        q.pop();
        vis[u] = 0;
        for (int i = 0; i < MAXN; i++)
            if (u == 0)
            {
                if (d[i] > d[u] + mp[u][i])
                {
                    d[i] = d[u] + mp[u][i];
                    if (!vis[i])
                        vis[i] = 1, q.push(i);
                }
            }
            else
            {
                if (d[i] > d[u] + mp[u][i] + 60)
                {
                    d[i] = d[u] + mp[u][i] + 60;
                    if (!vis[i])
                        vis[i] = 1, q.push(i);
                }
            }
    }
}
 
int main()
{
    //freopen("input.txt", "r", stdin);
    int nele, target, i, j;
    int t[10], d[MAXN];
    while (~scanf("%d%d%*c", &nele, &target))
    {
        memset(mp, 0, sizeof mp);
        for (i = 0; i < nele; i++)
            scanf("%d%*c", &t[i]);
        for (i = 0; i < MAXN; i++)
            for (j = 0; j < MAXN; j++)
                mp[i][j] = (i == j ? 0 : INF);
        char ch = 0;
        for (i = 0; i < nele; i++)
        {
            for (j = 0; ch != '\n'; j++)
                scanf("%d%c", &d[j], &ch);
            for (int k = 0; k < j; k++)
                for (int l = k + 1; l < j; l++)
                {
                    int &cur = mp[d[k]][d[l]];
                    cur = min(cur, abs(d[k] - d[l]) * t[i]);
                    mp[d[l]][d[k]] = cur;
                }
            ch = 0;
        }
        //Floyd();
        //Dijkstra(0);
        //SPFA(0);
        mp[0][target] == INF ? printf("IMPOSSIBLE\n") : printf("%d\n", mp[0][target]);
    }
    return 0;
}