提出了一个错误的算法 以为能优化到只运行两次dij
然而我还是too naive 还是乖乖dij n 次吧…
#include <iostream>
#include <string>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <queue>
#include <vector>
#include <set>
#include <algorithm>
#define INF 0x3F3F3F3F
using namespace std;typedef pair<int, int> pii;
struct cmp{
bool operator () (const pii a, const pii b){
return a.first > b.first;
}
};int map[][], val[][], lev[];
int m, n;int dij()
{
int dist[];
priority_queue<pii, vector<pii>, cmp> q;
memset(dist, 0x3f, sizeof dist);
dist[] = ;
q.push(make_pair(, ));
while(!q.empty()){
pii u = q.top();
q.pop();
if(u.first > dist[u.second]) continue;
for(int i = ; i <= n; i++){
if(dist[i] > dist[u.second] + val[u.second][i]){
dist[i] = dist[u.second] + val[u.second][i];
q.push(make_pair(dist[i], i));
}
}
}
return dist[];
}int main()
{
memset(map, 0x3f, sizeof val);
scanf("%d%d", &m, &n);
for(int i = ; i <= n; i++){
int x, y, p;
scanf("%d%d%d", &map[][i], &lev[i], &x);
while(x--){
scanf("%d%d", &y, &p);
map[y][i] = p;
}
}
int ans = INF;
for(int i = ; i <= m; i++){
memset(val, 0x3f, sizeof val);
for(int x = ; x <= n; x++){
if(x == || (lev[x] >= lev[] - m + i && lev[x] <= lev[] + i)){
for(int y = ; y <= n; y++){
if(lev[y] >= lev[] - m + i && lev[y] <= lev[] + i){
val[x][y] = map[x][y];
}
}
}
}
ans = min(dij(), ans);
//printf("%d ~ %d : %d\n", lev[1] - m + i, lev[1] + i, ans);
}
printf("%d\n", ans);
return ;
}