Submission #100153

#	Time	Username	Problem	Language	Result	Execution time	Memory
100153		aleksam	Evacuation plan (IZhO18_plan)	C++14	100 / 100	950 ms	30164 KiB

plan

//IZHO 2018 P2
#include <bits/stdc++.h>
#define INF INT_MAX
#define MOD 100000007
#define MAX_N 100000
#define MAX_M 100000
#define MAX_Q 100000

using namespace std;

struct edge{
	int d;
	int w;
};

struct dj{
	int v;
	int p;
	public:
		bool operator<(const dj& rhs) const{
    		return p>rhs.p;//Jer priroty queue vraca obrnuto
    	}
};

int N, M;
vector<edge> adj[MAX_N];
int height[MAX_N];
int query[MAX_Q][2];
int K, Q;
bool npp[MAX_N];

void input(){
	cin>>N>>M;
	for(int i=0; i<M; ++i){
		int a, b, w;
		cin>>a>>b>>w;
		a--;
		b--;
		edge ea, eb;
		ea.d=b;
		eb.d=a;
		ea.w=eb.w=w;
		adj[a].push_back(ea);
		adj[b].push_back(eb);
	}
	cin>>K;
	memset(npp, 0, sizeof(npp));
	for(int i=0; i<K; ++i){
		int g;
		cin>>g;
		g--;
		npp[g]=1;
	}
}

priority_queue<dj> pq;

void relax(int v){
	int d=adj[v].size();
	for(int i=0; i<d; ++i){
		int u=adj[v][i].d;
		int l=adj[v][i].w;
		if(height[u]>height[v]+l){
			height[u]=height[v]+l;
			dj un;
			un.p=height[u];
			un.v=u;
			pq.push(un);
		}
	}
}

void find_height(){
	memset(height, INF, sizeof(height));
	for(int i=0; i<N; ++i){
		if(npp[i]){
			height[i]=0;
		}
		else height[i]=INF;
	}
	for(int i=0; i<N; ++i){
		if(npp[i])relax(i);
	}
	while(!pq.empty()){
		int v=pq.top().v;
		pq.pop();
		if(npp[v])continue;
		relax(v);
		npp[v]=1;
	}
}

int p[MAX_N], rk[MAX_N];

dj vert[MAX_N];
int pt[MAX_N], inv[MAX_N];
int anc[MAX_N][20];
int depth[MAX_N];

void unionfindinit(){
	for(int i=0; i<N; ++i){
		p[i]=i;	
	}
}
int find(int a){
	if(a!=p[a])p[a]=find(p[a]);
	return p[a];
}


bool cmp(dj a, dj b){
	return a.p>b.p;
}

void maketree(){
	for(int i=0; i<N; ++i){
		vert[i].v=i;
		vert[i].p=height[i];
	}
	sort(vert, vert+N, cmp);
	memset(pt, -1, sizeof(pt));
	for(int i=0; i<N; ++i){
		inv[vert[i].v]=i;
	}
	for(int i=0; i<N; ++i){
		int v=vert[i].v;
		int d=adj[v].size();
		for(int j=0; j<d; ++j){
			int u=adj[v][j].d;
			int fu=find(u);
			if(inv[u]<inv[v] && fu!=v && pt[fu]==-1){
				u=fu;
				pt[u]=v;
				p[u]=v;
			}
		}
	}
	/*for(int i=0; i<N; ++i){
		printf("inv[%d]=%d\n", i, inv[i]);
	}
	for(int i=0; i<N; ++i){
		printf("pt[%d]=%d\n", i, pt[i]);
	}*/
}

void find_depth(int v){
	if(pt[v]==-1){
		depth[v]=0;
		return;
	}
	if(depth[pt[v]]==-1)
	find_depth(pt[v]);
	depth[v]=1+depth[pt[v]];
}
void lcainit(){
	memset(anc, -1, sizeof(anc));
	for(int i=0; i<N; ++i)
		anc[i][0]=pt[i];
	for(int l=1; l<17; ++l){
		for(int i=0; i<N; ++i){
			if(anc[i][l-1]!=-1)
			anc[i][l]=anc[anc[i][l-1]][l-1];
		}
	}
	memset(depth, -1, sizeof(depth));
	for(int i=0; i<N; ++i){
		if(depth[i]==-1)find_depth(i);
	}
}

int lca(int u, int v){
	if(depth[v]>depth[u])return lca(v, u);
	for(int l=16; l>=0; --l){
		if(depth[u]-depth[v]>=(1<<l))
			u=anc[u][l];
	}
	assert(depth[u]==depth[v]);
	if(u==v)return u;
	for(int l=16; l>=0; --l){
		if(anc[u][l]==anc[v][l])
			continue;
		u=anc[u][l];
		v=anc[v][l];
	}
	return pt[u];
}

int main(){
	ios::sync_with_stdio(false);
	input();
	find_height();

	unionfindinit();
	maketree();
	lcainit();
	cin>>Q;
	for(int i=0; i<Q; ++i){
		int s, t;
		cin>>s>>t;
		cout<<height[lca(s-1, t-1)]<<endl;
	}
	
	return 0;
}
/*
9 12
1 9 4
1 2 5
2 3 7
2 4 3
4 3 6
3 6 4
8 7 10
6 7 5
5 8 1
9 5 7
5 4 12
6 8 2
2
4 7
5
1 6
5 3
4 8
5 8
1 5

5 5
1 2 2
5 1 1
4 5 1
3 2 3
3 4 4
1
5
5
5 1
1 2
2 3
4 3
5 4
*/

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