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Submission #5432

# Submission time Handle Problem Language Result Execution time Memory
5432 2014-05-01T23:31:36 Z Qwaz Special graph (IZhO13_specialg) C++
100 / 100
 84 ms 22192 KB 
#include <cstdio>
#include <cmath>
#include <vector>

using namespace std;
const int MAX = 100020, BIT_MAX = 17;

int n, to[MAX], numQuery, qType[MAX], qA[MAX], qB[MAX];
vector < int > children[MAX];

void input(){
	scanf("%d", &n);

	int i;
	for(i = 1; i<=n; i++){
		scanf("%d", &to[i]);
		children[to[i]].push_back(i);
	}

	scanf("%d", &numQuery);
	for(i = 0; i<numQuery; i++){
		scanf("%d%d", &qType[i], &qA[i]);
		if(qType[i] == 2) scanf("%d", &qB[i]);
	}
}

int visited[MAX], cFull, cycleNum[MAX], cycleOrder[MAX], cycleSize[MAX];

int findCycle(int now, int visitNum){
	visited[now] = visitNum;

	if(visited[to[now]] == 0){
		int t = findCycle(to[now], visitNum);

		if(t != -1){
			cycleNum[now] = cFull;
			cycleOrder[now] = cycleOrder[to[now]]+1;
		} else {
			cycleNum[now] = -abs(cycleNum[to[now]]);
			cycleOrder[now] = cycleOrder[to[now]];
		}

		if(now == t) return -1;
		else return t;
	} else if(visited[to[now]] == visitNum){
		cycleNum[now] = ++cFull;
		cycleOrder[now] = 1;

		return to[now] == now ? -1 : to[now];
	} else {
		cycleNum[now] = -abs(cycleNum[to[now]]);
		cycleOrder[now] = cycleOrder[to[now]];
		return -1;
	}
}

int depth[MAX], p[20][MAX];

void calcDepth(int now){
	int i;
	for(i = 0; i<children[now].size(); i++){
		int nextNum = children[now][i];
		depth[nextNum] = depth[now]+1;
		calcDepth(nextNum);
	}
}

void init(){
	int i, v = 1;
	for(i = 1; i<=n; i++){
		if(visited[i] == 0)
			findCycle(i, v++);
	}

	for(i = 1; i<=n; i++){
		if(cycleNum[i] < 0){
			if(cycleNum[to[i]] == cycleNum[i]) p[0][i] = to[i];
			else {
				p[0][i] = i;
				depth[i] = 1;
				calcDepth(i);
			}
		} else {
			cycleSize[cycleNum[i]]++;
			p[0][i] = i;
		}
	}

	int lvl = 1;
	for(lvl = 1; lvl<=BIT_MAX; lvl++){
		for(i = 1; i<=n; i++)
			p[lvl][i] = p[lvl-1][p[lvl-1][i]];
	}
}

int uf[MAX], firstCut[MAX];
bool cycleOK[MAX];

int getParent(int num){
	if(uf[num] == num) return num;
	return uf[num] = getParent(uf[num]);
}

void link(int a, int b){
	if(getParent(a) == getParent(b)){
		cycleOK[cycleNum[a]] = 1;
	} else {
		uf[getParent(a)] = getParent(b);
	}
}

void cut(){
	int i, tNext[MAX];
	for(i = 1; i<=n; i++){
		tNext[i] = to[i];
		uf[i] = i;
	}

	for(i = 0; i<numQuery; i++){
		if(qType[i] == 1){
			int cn = cycleNum[qA[i]];
			if(cn > 0 && firstCut[cn] == 0){
				firstCut[cn] = cycleOrder[qA[i]];
			}
			tNext[qA[i]] = 0;
		}
	}

	for(i = 1; i<=n; i++){
		if(tNext[i]){
			link(i, tNext[i]);
		}
	}
}

int cycleDist(int f, int s){
	int cn = cycleNum[f];
	if(f == s || cycleOK[cn] ||
	   (cycleOrder[f] > cycleOrder[s]
	   ? !(cycleOrder[f] >= firstCut[cn] && firstCut[cn] > cycleOrder[s])
	   : !(cycleOrder[f] >= firstCut[cn] || firstCut[cn] > cycleOrder[s]))){
		int cs = cycleSize[cn];
		return (cycleOrder[f]-cycleOrder[s]+cs) % cs;
	} else return -1;
}

int res[MAX];

void solve(){
	int i;
	for(i = numQuery-1; i>=0; i--){
		if(qType[i] == 1){
			link(qA[i], to[qA[i]]);
		} else {
			res[i] = -1;

			int f = qA[i], s = qB[i];
			if(getParent(f) == getParent(s)){
				if(cycleNum[s] > 0){
					if(cycleNum[f] == cycleNum[s]){
						//사이클 -> 사이클
						res[i] = cycleDist(f, s);
					} else if(cycleNum[f] == -cycleNum[s]){
						//트리 -> 사이클
						int t = cycleDist(to[p[BIT_MAX][f]], s);
						if(t != -1)
							res[i] = depth[f]+t;
					}
				} else {
					if(cycleNum[f] == cycleNum[s] && cycleOrder[f] == cycleOrder[s] && depth[s] < depth[f]){
						//트리 -> 트리
						int dist = depth[f]-depth[s];

						int t;
						for(t = 0; t<=BIT_MAX; t++){
							if(dist & (1<<t)){
								f = p[t][f];
							}
						}

						if(f == s)
							res[i] = dist;
					}
				}
			}
		}
	}

	for(i = 0; i<numQuery; i++){
		if(qType[i] == 2){
			printf("%d\n", res[i]);
		}
	}
}

int main(){
	input();

	init();
	cut();

	solve();

	return 0;
}

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 16416 KB Output is correct
2 Correct 0 ms 16424 KB Output is correct
3 Correct 4 ms 16420 KB Output is correct
4 Correct 4 ms 16420 KB Output is correct
5 Correct 4 ms 16416 KB Output is correct
6 Correct 12 ms 16424 KB Output is correct
7 Correct 12 ms 16420 KB Output is correct
8 Correct 8 ms 16424 KB Output is correct
9 Correct 12 ms 16424 KB Output is correct
10 Correct 8 ms 16420 KB Output is correct
11 Correct 84 ms 22188 KB Output is correct
12 Correct 68 ms 18260 KB Output is correct
13 Correct 76 ms 19104 KB Output is correct
14 Correct 56 ms 18004 KB Output is correct
15 Correct 64 ms 18444 KB Output is correct
16 Correct 68 ms 18280 KB Output is correct
17 Correct 80 ms 19968 KB Output is correct
18 Correct 72 ms 19964 KB Output is correct
19 Correct 76 ms 19972 KB Output is correct
20 Correct 72 ms 22192 KB Output is correct