Submission #17566

#	Time	Username	Problem	Language	Result	Execution time	Memory
17566		gs14004	Special graph (IZhO13_specialg)	C++14	0 / 100	97 ms	19336 KiB

specialg

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <limits.h>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <algorithm>
#include <string>
#include <functional>
#include <vector>
#include <numeric>
#include <deque>
#include <bitset>
#include <iostream>
using namespace std;
typedef long long lint;
typedef long double llf;
typedef pair<int,int> pi;

struct disj{
	int pa[100005];
	void init(int n){
		for(int i=0; i<=n; i++) pa[i] = i;
	}
	int find(int x){
		return pa[x] = (pa[x] == x ? x : find(pa[x]));
	}
	bool uni(int p, int q){
		p = find(p), q = find(q);
		if(p == q) return 0;
		pa[q] = p; return 1;
	}
}disj;

struct query{
	int t, a, b;
}q[100005];

int n, m, a[100005], kill[100005];
vector<int> graph[100005], rev[100005];

int indeg[100005];
int cyclab[100005], cycidx[100005], cycsz[100005], cycp; 
int treein[100005], treeout[100005], root[100005], dep[100005], treep; 

void dfs(int x, int r){
	treein[x] = ++treep;
	root[x] = r;
	for(auto &i : rev[x]){
		if(cyclab[i]) continue;
		dep[i] = dep[x] + 1;
		dfs(i, r);
	}
	treeout[x] = ++treep;
}

void proc_tree(){
	for(int i=1; i<=n; i++){
		if(a[i] == 0 || cyclab[i]){
			dfs(i, i);
		}
	}
}

queue<int> que;

void proc_cycle(){
	for(int i=1; i<=n; i++){
		if(indeg[i] == 0) que.push(i);
	}
	while(!que.empty()){
		int x = que.front();
		que.pop();
		if(!a[x]) continue;
		indeg[a[x]]--;
		if(indeg[a[x]] == 0) que.push(a[x]);
	}
	for(int i=1; i<=n; i++){
		if(indeg[i] && !cyclab[i]){
			int p = i;
			cycp++;
			while(!cyclab[p]){
				cyclab[p] = cycp;
				cycidx[p] = ++cycsz[cycp];
				p = a[p];
			}
		}
	}
}

inline bool inside(int a, int b){
	return treein[a] <= treein[b] && treeout[b] <= treeout[a];
}

int solve(int p, int q){
	if(cyclab[p] && cyclab[q]){
		int dx = cycidx[q] - cycidx[p] + cycsz[cyclab[p]];
		dx %= cycsz[cyclab[p]];
		return dx;
	}
	if(cyclab[p] && !cyclab[q]){
		return -1;
	}
	if(!cyclab[p] && cyclab[q]){
		return dep[p] + solve(root[p], q);
	}
	if(inside(q, p)){
		return dep[p] - dep[q];
	}
	return -1;
}

int main(){
	cin >> n;
	for(int i=1; i<=n; i++){
		scanf("%d",&a[i]);
		kill[i] = (a[i] == 0);
		if(a[i]){
			rev[a[i]].push_back(i);
			graph[i].push_back(a[i]);
			indeg[a[i]]++;
		}
	}
	cin >> m;
	for(int i=0; i<m; i++){
		scanf("%d",&q[i].t);
		if(q[i].t == 1){
			scanf("%d",&q[i].a);
			kill[q[i].a] = 1;
		}
		else{
			scanf("%d %d",&q[i].a, &q[i].b);
		}
	}
	reverse(q, q+m);
	proc_cycle();
	proc_tree();
	disj.init(n);
	for(int i=1; i<=n; i++){
		if(!kill[i]) disj.uni(i, a[i]);
	}
	vector<int> stk;
	for(int i=0; i<m; i++){
		if(q[i].t == 1){
			disj.uni(q[i].a, a[q[i].a]);
		}
		else{
			if(disj.find(q[i].a) != disj.find(q[i].b)) stk.push_back(-1);
			else stk.push_back(solve(q[i].a, q[i].b));
		}
	}
	while(!stk.empty()){
		printf("%d\n",stk.back());
		stk.pop_back();
	}
}

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