hdu 4784 Dinner Coming Soon

时间:2023-03-10 01:19:08
hdu 4784 Dinner Coming Soon

spfa+优先队列。刚开始只用的spfa,结果tle到死。然后听队友说要用到优先队列,想了想,对时间分层的话的确每一个结点都只进队列一次即可,因为只有大时间才能更新出小时间,然后就wa成shi了。按队友写的改了才过得,好伤心的说,这是好题。。。

附上代码供大家对拍吧。

#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<queue>
#include<cmath>
#define LL long long
#define CLR(a, b) memset(a, b, sizeof(a))
#define REP(i, n) for(int i = 0; i < n; i ++)
#define FF(i, a, b) for(int i = a; i < b; i ++)
#define FD(i, a, b) for(int i = a; i >= b; i --)
#define swp(a, b) a^=b^=a^=b; using namespace std; struct Node
{
int u, b, vd, t;
Node(){}
Node(int a, int b, int c, int d):u(a), b(b), vd(c), t(d){}
bool operator < (const Node &rhs) const
{
return t < rhs.t;
}
}; struct Edge
{
int u, v, t, m;
Edge(){}
Edge(int a, int b, int c, int d):u(a), v(b), t(c), m(d){}
}E[420]; int fir[220], next[440], tot; void Add_Edge(int u, int v, int t, int m)
{
E[tot] = Edge(u, v, t, m);
next[tot] = fir[u]; fir[u] = tot ++;
} int dp[110][6][7][220];
bool vis[110][6][7][220];
int p[110][7];
int N, M, B, K, R, T; priority_queue<Node>q; void relax(int u, int b, int vd, int t, int val)
{
if ((u == 1 || u == N) && vd != 0) return ;
if(dp[u][b][vd][t] < val)
{
dp[u][b][vd][t] = val;
if(!vis[u][b][vd][t])
{
Node w = Node(u, b, vd, t);
q.push(w);
vis[u][b][vd][t] = true;
}
}
} void spfa()
{
int u, v, m, t,vd, b;
Node a = Node(1, 0, 0, T);
CLR(dp, -1);CLR(vis, false);
dp[1][0][0][T] = R;
vis[1][0][0][T] = true;
q.push(a);
while(!q.empty())
{
a = q.top();q.pop();
u = a.u;b = a.b;vd = a.vd;t = a.t;
if(u == N) continue;
if(t > 0)
{
int val = dp[u][b][vd][t];
relax(u, b, (vd + 1) % K, t - 1, val);
if(p[u][vd] != -1)
{
if(b > 0)
{
relax(u, b - 1, (vd + 1) % K, t - 1, val + p[u][vd]);
}
if(b < B && val >= p[u][vd])
{
relax(u, b + 1, (vd + 1) % K, t - 1, val - p[u][vd]);
}
}
}
for(int i = fir[u]; ~i; i = next[i])
{
int tmp = t - E[i].t;
if(tmp < 0) continue;
v = E[i].v;
int val = dp[u][b][vd][t] - E[i].m;
if(val < 0) continue;
relax(v, b, vd, tmp, val);
if(p[u][vd] != -1)
{
if(b > 0)
{
relax(v, b - 1, vd, tmp, val + p[u][vd]);
}
if(b < B && val >= p[u][vd])
{
relax(v, b + 1, vd, tmp, val - p[u][vd]);
}
}
}
}
} int main()
{
int Time, cas = 1;
scanf("%d", &Time);
while(Time --)
{
scanf("%d%d%d%d%d%d", &N, &M, &B, &K, &R, &T);
for(int i = 0; i < K; i ++)
{
for(int j = 1; j <= N; j ++)
{
scanf("%d", &p[j][i]);
}
}
CLR(fir, -1);tot = 0;
int u, v, t, m;
for(int i = 0; i < M; i ++)
{
scanf("%d%d%d%d", &u, &v, &t, &m);
Add_Edge(u, v, t, m);
}
spfa();
int ans = -1;
for(int i = 0; i <= B; i ++)
{
for(int j = 0; j <= T; j ++)
{
ans = max(ans, dp[N][i][0][j]);
}
}
if(ans != -1) printf("Case #%d: %d\n", cas ++, ans);
else printf("Case #%d: Forever Alone\n", cas ++);
}
}