HDU 2923 Einbahnstrasse 最短路 Dijkstra

/*
 * 解題總結 :
 *      1 : 寫的有點複雜了，但整體還是蠻清晰的。
 *      2 : 還是一個map和一個變量分配id，建圖過程複雜了點。
 *      3 : 正着跑一遍最短路，然後反向建圖跑一遍最短路。
 */
#include <bits/stdc++.h>
using namespace std;
const int MAXN = 2e3 + 10;
const int MAXM = 2e4 + 10;
const int INF = 0x3f3f3f3f;

struct input{
    int u, v, w;
    string midstr;
}ds[MAXM];
struct E{
    int to, w, nxt;
}edge[MAXM];
map<string, int> M;
priority_queue<pair<int, int>> Q;
int tot, head[MAXN], dis[MAXN], n, C, R, tim;
string e[MAXN];
bool use[MAXN];

inline void clear(){
    tot = 0;
    memset(head, -1, sizeof head);
    while(!Q.empty()) Q.pop();
    memset(dis, INF, sizeof dis);
    dis[1] = 0;
    memset(use, false, sizeof use);
}

inline void addedge(int u, int v, int w){
    edge[tot].to = v;
    edge[tot].w = w;
    edge[tot].nxt = head[u];
    head[u] = tot++;
}

inline int getw(string ss){
    int m = ss.size(), ans = 0;
    for(int i = 0; i < m; ++i){
        if(isdigit(ss[i])){
            while(i < m && isdigit(ss[i])) ans = ans * 10 + ss[i++] - '0';
            return ans;
        }
    }
}

inline void dijkstra(){
    Q.push({0, 1});
    while(!Q.empty()){
        auto it = Q.top();
        Q.pop();
        int id = it.second;
        if(use[id]) continue;
        use[id] = true;
        for(int i = head[id]; ~i; i = edge[i].nxt){
            int to = edge[i].to;
            int w = edge[i].w;
            if(dis[id] + w < dis[to]){
                dis[to] = dis[id] + w;
                Q.push({-dis[to], to});
            }
        }
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    //cout << setiosflags(ios::fixed) << setprecision(1); //保留小數點後1位
    //cout << setprecision(1); //保留1位有效數字
//    freopen("in.txt", "r", stdin);
//    freopen("out.txt", "w", stdout);

    int cas = 1;
    while(cin >> n >> C >> R){
        if(n == 0 && C == 0 && R == 0) break;
        clear();
        M.clear();
        tim = 0;
        for(int i = 1; i <= C + 1; ++i) {
            cin >> e[i];
            if(M[e[i]] == 0) M[e[i]] = ++tim;
        }
        for(int i = 1; i <= R; ++i){
            string strs, stre, midstr;
            cin >> strs >> midstr >> stre;
            if(M[strs] == 0) M[strs] = ++tim;
            if(M[stre] == 0) M[stre] = ++tim;
            int w = getw(midstr);
            if(midstr[0] == '<') addedge(M[stre], M[strs], w);
            if(midstr[midstr.size() - 1] == '>') addedge(M[strs], M[stre], w);
            ds[i].u = M[strs];
            ds[i].v = M[stre];
            ds[i].w = w;
            ds[i].midstr = midstr;
        }
        dijkstra();
        int ans = 0;
        for(int i = 2; i <= C + 1; ++i) ans += dis[M[e[i]]];
        clear();
        for(int i = 1; i <= R; ++i){
            string midstr = ds[i].midstr;
            if(midstr[0] == '<') addedge(ds[i].u, ds[i].v, ds[i].w);
            if(midstr[midstr.size() - 1] == '>') addedge(ds[i].v, ds[i].u, ds[i].w);
        }
        dijkstra();
        for(int i = 2; i <= C + 1; ++i) ans += dis[M[e[i]]];
        cout << cas++ << ". " << ans << endl;
    }
    return 0;
}