【题目链接】
【算法】
最短路，注意不能用dijkstra，要用SPFA
【代码】
#include <algorithm> #include <bitset> #include <cctype> #include <cerrno> #include <clocale> #include <cmath> #include <complex> #include <cstdio> #include <cstdlib> #include <cstring> #include <ctime> #include <deque> #include <exception> #include <fstream> #include <functional> #include <limits> #include <list> #include <map> #include <iomanip> #include <ios> #include <iosfwd> #include <iostream> #include <istream> #include <ostream> #include <queue> #include <set> #include <sstream> #include <stdexcept> #include <streambuf> #include <string> #include <utility> #include <vector> #include <cwchar> #include <cwctype> #include <stack> #include <limits.h> using namespace std; #define MAXN 100 typedef long long LL; LL i,M,N,x,t,v,ans,p; LL dist[MAXN+10],vis[MAXN+10],level[MAXN+10]; vector<pair<LL,LL> > E[MAXN+10]; template <typename T> void read(T &x) { int f=1; char c = getchar(); x=0; for (; !isdigit(c); c = getchar()) { if (c=='-') f=-1; } for (; isdigit(c); c = getchar()) x=x*10+c-'0'; x*=f; } void spfa(int low,int high) { int i,to,cost; queue<LL> q; memset(vis,0,sizeof(vis)); for (i = 1; i <= N; i++) dist[i] = 2e9; dist[0] = 0; vis[0] = 1; q.push(0); while (!q.empty()) { x = q.front(); q.pop(); vis[x] = 0; for (i = 0; i < E[x].size(); i++) { to = E[x][i].first; cost = E[x][i].second; if ((level[to] >= low) && (level[to] <= high)) { if (dist[x] + cost < dist[to]) { dist[to] = dist[x] + cost; if (!vis[to]) { vis[to] = 1; q.push(to); } } } } } } int main() { read(M); read(N); for (i = 1; i <= N; i++) { read(p); read(level[i]); read(x); E[0].push_back(make_pair(i,p)); while (x--) { read(t); read(v); E[t].push_back(make_pair(i,v)); } } ans = 2e9; for (i = level[1] - M; i <= level[1]; i++) { spfa(i,i+M); ans = min(ans,dist[1]); } cout<< ans << endl; return 0; }