mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
100 lines
2.4 KiB
C++
100 lines
2.4 KiB
C++
#include <iostream>
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#include <cstdio>
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#include <cstring>
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#include <queue>
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using namespace std;
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const int N=105;
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int head[N],tot;
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int dp[N][N*5];
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struct Edge
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{
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int from,to,cost,pre;
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Edge(){}
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Edge(int a,int b,int c,int d){from=a;to=b;cost=c;pre=d;}
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}edge[N*3];
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void addEdge(int u,int v,int cost)
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{
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edge[tot]=Edge(u,v,cost,head[u]);
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head[u]=tot++;
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}
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int spfa(int st,int ed)
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{
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queue<int> que;
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int vis[N],dis[N],pre[N];
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memset(vis,0,sizeof(vis));
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memset(dis,0x7f,sizeof(dis));
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memset(pre,-1,sizeof(pre));
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que.push(st);
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vis[st]=1; dis[st]=0;
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while(!que.empty())
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{
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int u=que.front();
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que.pop(); vis[u]=0;
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for(int i=head[u];i!=-1;i=edge[i].pre)
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{
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int v=edge[i].to,cost=edge[i].cost;
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if(dis[v]>dis[u]+cost)
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{
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dis[v]=dis[u]+cost;
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pre[v]=i;
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if(!vis[v])
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{
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vis[v]=1;
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que.push(v);
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}
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}
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}
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}
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for(int i=ed;i!=st;i=edge[pre[i]].from)
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{
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edge[pre[i]].cost=0;
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edge[pre[i]^1].cost=0;
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}
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return dis[ed];
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}
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void dfs(int u,int fa,int coin)
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{
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for(int e=head[u];e!=-1;e=edge[e].pre)
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{
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int v=edge[e].to,cost=edge[e].cost*2;
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if(v==fa||coin<cost) continue;
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dfs(v,u,coin-cost);
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for(int i=coin;i>=cost;i--)
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{
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for(int j=0;j+cost<=i;j++)
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{
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if(dp[u][i-j-cost]!=-1&&dp[v][j]!=-1)
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dp[u][i]=max(dp[u][i],dp[u][i-j-cost]+dp[v][j]);
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}
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}
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}
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}
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int main()
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{
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int n,t;
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while(scanf("%d%d",&n,&t)!=EOF)
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{
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tot=0;
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memset(dp,-1,sizeof(dp));
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memset(head,-1,sizeof(head));
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for(int i=0;i<n-1;i++)
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{
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int a,b,c;
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scanf("%d%d%d",&a,&b,&c);
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addEdge(a,b,c);
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addEdge(b,a,c);
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}
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for(int i=1;i<=n;i++) scanf("%d",&dp[i][0]);
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t-=spfa(1,n);
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if(t<0) puts("Human beings die in pursuit of wealth, and birds die in pursuit of food!");
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else
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{
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dfs(1,0,t);
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int res=0;
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for(int i=0;i<=t;i++) res=max(res,dp[1][i]);
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printf("%d\n",res);
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}
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}
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return 0;
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}
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