题意:有N个点,M条边,每个点有权值,问从起点到终点最短路的个数以及权值最大的最短路的权值。
分析:修改Dijstra模板。
#include<bits/stdc++.h>
using namespace std;
const int INT_INF = 0x3f3f3f3f;
const int MAXN = 500 + 10;
int weight[MAXN];
typedef long long LL;
struct Edge{
int from, to;
LL dist;
Edge(int f, int t, LL d):from(f), to(t), dist(d){}
};
struct HeapNode{
LL d;
int u;
HeapNode(LL dd, int uu):d(dd), u(uu){}
bool operator < (const HeapNode& rhs)const{
return d > rhs.d;
}
};
struct Dijkstra{
int n, m;
vector<Edge> edges;
vector<int> G[MAXN];
LL d[MAXN];
int num[MAXN];
int value[MAXN];
bool done[MAXN];
void init(int n){
this -> n = n;
for(int i = 0; i <= n; ++i) G[i].clear();
edges.clear();
}
void AddEdge(int from, int to, LL dist){
edges.push_back(Edge(from, to, dist));
m = edges.size();
G[from].push_back(m - 1);
}
void dijkstra(int s){
priority_queue<HeapNode> Q;
for(int i = 0; i <= n; ++i){
d[i] = 0x3f3f3f3f3f3f3f3f;
}
memset(done, false, sizeof done);
d[s] = 0;
num[s] = 1;
value[s] = weight[s];
Q.push(HeapNode(0, s));
while(!Q.empty()){
HeapNode x = Q.top();
Q.pop();
int u = x.u;
if(done[u]) continue;
done[u] = true;
for(int i = 0; i < G[u].size(); ++i){
Edge &e = edges[G[u][i]];
if(d[e.to] > d[u] + e.dist) {
d[e.to] = d[u] + e.dist;
num[e.to] = num[u];
value[e.to] = value[u] + weight[e.to];
Q.push(HeapNode(d[e.to], e.to));
}
else if(d[e.to] == d[u] + e.dist){
num[e.to] += num[u];
if(value[u] + weight[e.to] > value[e.to]){
value[e.to] = value[u] + weight[e.to];
}
}
}
}
}
}dij;
int main(){
int n, m, st, et;
scanf("%d%d%d%d", &n, &m, &st, &et);
for(int i = 0; i < n; ++i){
scanf("%d", &weight[i]);
}
dij.init(n);
int x, y;
LL l;
for(int i = 0; i < m; ++i){
scanf("%d%d%lld", &x, &y, &l);
dij.AddEdge(x, y, l);
dij.AddEdge(y, x, l);
}
dij.dijkstra(st);
printf("%d %d\n", dij.num[et], dij.value[et]);
return 0;
}