Submission #334344

#	Time	Username	Problem	Language	Result	Execution time	Memory
334344		juggernaut	Evacuation plan (IZhO18_plan)	C++14	0 / 100	530 ms	51472 KiB

plan

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int n,m,dis[100005],par[100005],sz[100005],up[100005][17],mn[100005][17],tin[100005],tout[100005],timer;
struct data{
    int x,y,z;
};
int fin(int v){
    return v==par[v]?v:par[v]=fin(par[v]);
}
vector<pair<int,int>>g[100005];
void dfs(int v,int p,int val){
    tin[v]=++timer;
    up[v][0]=p;
    mn[v][0]=val;
    for(int i=1;i<17;i++){
        up[v][i]=up[up[v][i-1]][i-1];
        mn[v][i]=min(mn[v][i-1],mn[up[v][i-1]][i-1]);
    }
    for(auto to:g[v])if(to.first!=p)dfs(to.first,v,to.second);
    tout[v]=++timer;
}
bool upper(int a,int b){
	return tin[a]<=tin[b]&&tout[a]>=tout[b];
}
vector<data>edge,vec;
int lca(int a,int b){
    if(upper(a,b))return a;
    if(upper(b,a))return b;
    for(int i=16;i>=0;i--)
    if(!upper(up[a][i],b))a=up[a][i];
    return up[a][0];
}
bool cmp(data l,data r){
    return l.z>r.z;
}
int go(int v,int l){
    int res=2e9;
    for(int i=16;i>=0;i--){
        if(!upper(up[v][i],l)){
            res=min(res,mn[v][i]);
            v=up[v][i];
        }
    }
    return res;
}
int main(){
    scanf("%d%d",&n,&m);
    while(m--){
        data e;
        scanf("%d%d%d",&e.x,&e.y,&e.z);
        edge.push_back(e);
        g[e.x].push_back({e.y,e.z});
        g[e.y].push_back({e.x,e.z});
    }
    for(int i=1;i<=n;i++)dis[i]=2e9;
    scanf("%d",&m);
    priority_queue<pair<int,int>>q;
    while(m--){
        int x;
        scanf("%d",&x);
        dis[x]=0;
        q.push({0,x});
    }
    while(!q.empty()){
        int v=q.top().second;
        int val=-q.top().first;
        q.pop();
        if(val>dis[v])continue;
        for(auto to:g[v]){
            if(dis[to.first]>val+to.second){
                dis[to.first]=val+to.second;
                q.push({-dis[to.first],to.first});
            }
        }
    }
    for(int i=1;i<=n;i++){
        sz[i]=1,par[i]=i;
        g[i].clear();
    }
    for(auto to:edge){
        data e;
        e=to;
        e.z=min(dis[to.x],dis[to.y]);
        vec.push_back(e);
    }
    sort(vec.begin(),vec.end(),cmp);
    for(auto to:vec){
        int x=fin(to.x);
        int y=fin(to.y);
        if(x!=y){
            if(sz[x]<sz[y])swap(x,y);
            sz[x]+=sz[y];
            par[y]=x;
            g[to.x].push_back({to.y,to.z});
            g[to.y].push_back({to.x,to.z});
            //cout<<to.x<<" "<<to.y<<" "<<to.z<<endl;
        }
    }
    dfs(1,1,2e9);
    scanf("%d",&m);
    while(m--){
        int x,y;
        scanf("%d%d",&x,&y);
        int l=lca(x,y);
        printf("%d\n",min(go(x,l),go(y,l)));
    }
}

Compilation message (stderr)

plan.cpp: In function 'int main()':
plan.cpp:48:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   48 |     scanf("%d%d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~
plan.cpp:51:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   51 |         scanf("%d%d%d",&e.x,&e.y,&e.z);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
plan.cpp:57:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   57 |     scanf("%d",&m);
      |     ~~~~~^~~~~~~~~
plan.cpp:61:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   61 |         scanf("%d",&x);
      |         ~~~~~^~~~~~~~~
plan.cpp:101:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  101 |     scanf("%d",&m);
      |     ~~~~~^~~~~~~~~
plan.cpp:104:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  104 |         scanf("%d%d",&x,&y);
      |         ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 13
• Subtask 3: 0 / 12
• Subtask 4: 0 / 19
• Subtask 5: 0 / 46