HDU - 2112 HDU Today Dijkstra

注意：

1、去重边

2、终点和起点一样，应当输出0

3、是无向图

AC代码

#include <cstdio>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <utility>
#include <string>
#include <iostream>
#include <map>
#include <set>
#include <vector>
#include <queue>
#include <stack>
using namespace std;
#define eps 1e-10
#define inf 0x3f3f3f3f
#define PI pair<int, int>
typedef long long LL;
const int maxn = 150 + 5;
int vis[maxn], d[maxn], w[maxn][maxn];
map<string, int>Hash;
int cur;

int get_ID(string &p) {
	if(!Hash.count(p)) Hash[p] = cur++;
	return Hash[p];
}

struct point{
	int d, u;
	point(){
	}
	point(int d, int u):d(d), u(u) {
	}
	bool operator < (const point& p) const {
		return d > p.d;
	}
};

string s, e;
int dijkstra(int n) {
	int x = get_ID(s), y = get_ID(e);
	for(int i = 0; i < n; ++i) d[i] = inf;
	d[x] = 0;
	memset(vis, 0, sizeof(vis));
	priority_queue<point>Q;
	Q.push(point(0, x)); //将起点加入队列
	while(!Q.empty()) {
		point p = Q.top(); Q.pop();
		int u = p.u;
		if(u == y) return d[y];
		if(vis[u]) continue;
		vis[u] = 1;
		for(int i = 0; i < n; ++i) {
			if(d[i] > d[u] + w[u][i]) { //update
				d[i] = d[u] + w[u][i];
				if(d[i] > inf) d[i] = inf;
				Q.push(point(d[i], i));
			}
		}
	}
	return -1;
}

int main() {
	int n;
	while(scanf("%d", &n) == 1 && n != -1) {
		memset(w, inf, sizeof(w));
		Hash.clear();
		cur = 0;
		cin >> s >> e;
		string x, y;
		int cost;
		for(int i = 0; i < n; ++i) {
			cin >> x >> y >> cost;
			int u = get_ID(x), v = get_ID(y);
			w[v][u] = w[u][v] = min(w[u][v], cost); //去重边
		}
		printf("%d\n", dijkstra(Hash.size()));
	}
	return 0;
}

如有不当之处欢迎指出！