J - Invitation Cards——最短路_spfa()算法

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>

using namespace std;

const int inf = 0x3f3f3f3f;
const int N = 1e6 + 4;
const int M = 1e6 + 4;

struct Edge{
int v;
int w;
int next;
}e1[M*2], e2[M*2];

int n, m, cnt1, cnt2, head1
, head2
, dis
, vis
;

int add_edge(int u, int v, int w, struct Edge e[M*2], int head
, int cnt);
void spfa(int x, struct Edge e[M*2], int head
);

int main(){
int T, i, u, v, w;
long long sum;
scanf("%d", &T);
while(T--){
scanf("%d %d", &n, &m);
sum = 0, cnt1 = cnt2 = 0;
memset(head1, -1, sizeof(head1));
memset(head2, -1, sizeof(head2));
for(i = 1; i <= m; i++){
scanf("%d %d %d", &u, &v, &w);
cnt1 = add_edge(u, v, w, e1, head1, cnt1);
cnt2 = add_edge(v, u, w, e2, head2, cnt2);
}
spfa(1, e1, head1);
for(i = 1; i <= n; i++){
sum += dis[i];
}
spfa(1, e2, head2);
for(i = 1; i <= n; i++){
sum += dis[i];
}
printf("%lld\n", sum);
}
return 0;
}
int add_edge(int u, int v, int w, struct Edge e[M*2], int head
, int cnt){
e[cnt].v = v;
e[cnt].w = w;
e[cnt].next = head[u];
head[u] = cnt++;
return cnt;
}
void spfa(int x, struct Edge e[M*2], int head
){
queue <int> q;
while(!q.empty()){
q.pop();
}
memset(dis, inf, sizeof(dis));
memset(vis, 0, sizeof(vis));
dis[x] = 0, vis[x] = 1;
q.push(x);
while(!q.empty()){
int t1 = q.front();
q.pop();
vis[t1] = 0;
for(int i = head[t1]; ~i; i = e[i].next){
if(dis[t1] + e[i].w < dis[e[i].v]){
dis[e[i].v] = dis[t1] + e[i].w;
if(!vis[e[i].v]){
vis[e[i].v] = 1;
q.push(e[i].v);
}
}
}
}
}