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68 lines
1.7 KiB
C++
68 lines
1.7 KiB
C++
#define _CRT_SECURE_NO_WARNINGS
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#define _SILENCE_CXX17_C_HEADER_DEPRECATION_WARNING
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#include <bits/stdc++.h>
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using namespace std;
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unordered_map<string, int> m;
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int getId(const char *str)
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{
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auto ite = m.find(str);
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if (ite != m.end())
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return ite->second;
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else
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return m[str] = m.size();
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}
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const int N = 20050;
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int adj[N], nxt[N], to[N], len[N], dis[N], ecnt;
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inline void addEdge(int f, int t, int l)
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{
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ecnt++;
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nxt[ecnt] = adj[f];
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adj[f] = ecnt;
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to[ecnt] = t;
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len[ecnt] = l;
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}
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inline void rst()
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{
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m.clear();
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ecnt = 0;
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memset(adj, 0, sizeof(adj));
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memset(dis, 0x3f3f3f3f, sizeof(dis));
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}
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char buf1[50], buf2[50];
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struct node
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{
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int u, w;
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};
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bool operator<(const node x, const node y) noexcept { return x.w > y.w; }
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priority_queue<node> h;
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int main()
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{
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int n;
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while (scanf("%d", &n), ~n)
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{
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rst();
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scanf("%s%s", buf1, buf2);
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int S = getId(buf1), T = getId(buf2);
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for (int i = 0, x, y, z; i < n; i++)
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{
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scanf("%s%s%d", buf1, buf2, &z);
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x = getId(buf1), y = getId(buf2);
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addEdge(x, y, z), addEdge(y, x, z);
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}
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dis[S] = 0;
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h.push({S, dis[S]});
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while (!h.empty())
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{
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auto u = h.top().u, w = h.top().w;
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h.pop();
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if (w != dis[u]) continue;
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for (int e = adj[u]; e; e = nxt[e])
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if (dis[to[e]] > w + len[e])
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dis[to[e]] = w + len[e], h.push({to[e], dis[to[e]]});
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}
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if (dis[T] > 15000) dis[T] = -1;
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printf("%d\n", dis[T]);
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}
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return 0;
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}
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