oj.uz

Submission #35069

# Submission time Handle Problem Language Result Execution time Memory
35069 2017-11-17T22:12:18 Z model_code One-Way Streets (CEOI17_oneway) C++11
100 / 100
 273 ms 31608 KB 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <iostream>
#include <sstream>
#include <vector>
#include <string>
#include <math.h>
#include <queue>
#include <list>
#include <algorithm>
#include <map>
#include <set>
#include <stack>
#include <ctime>
#include <iterator>
using namespace std;

#define ALL(c) (c).begin(),(c).end()
#define IN(x,c) (find(c.begin(),c.end(),x) != (c).end())
#define REP(i,n) for (int i=0;i<(int)(n);i++)
#define FOR(i,a,b) for (int i=(a);i<=(b);i++)
#define INIT(a,v) memset(a,v,sizeof(a))
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
template<class A, class B> A cvt(B x) { stringstream ss; ss<<x; A y; ss>>y; return y; }

typedef pair<int,int> PII;
typedef long long int64;

#define N 100000
#define M 100000
#define P 100000

mt19937 rnd(time(0));

int n,m,q;
vector<PII> adj[N];
int edge[M][2];
int path[P][3];

int bridge[M];
int comp[N];
char label[M+1];
vector<PII> adjc[N];

int t=0;
int lo[N],ind[N];

void tarjan(int x, int par=-1) {
	ind[x]=t; lo[x]=t;
	t++;
	for (PII yi : adj[x]) {
		int y=yi.first, i=yi.second;
		if (i==par) continue;
		if (ind[y]==-1) {
			tarjan(y,i);
			lo[x]=min(lo[x], lo[y]);
			if (lo[y]>ind[x]) bridge[i]=1;
		} else {
			lo[x]=min(lo[x], ind[y]);
		}
	}
}

int v[N];

void components(int x, int c) {
	v[x]=1;
	comp[x]=c;
	for (PII yi : adj[x]) {
		int y=yi.first, i=yi.second;
		if (!v[y] && !bridge[i]) components(y,c);
	}
}

int depth[N];
int parent[N][2];

void dfs(int x, int d=0, int par=-1, int pari=-1) {
	depth[x]=d;
	parent[x][0]=par; parent[x][1]=pari;
	for (PII yi : adjc[x]) {
		int y=yi.first, i=yi.second;
		if (y!=par) dfs(y,d+1,x,i);
	}
}

#define K 18
int p[N][K];

void LCA_init(int c) {
	INIT(p,-1);
	REP (i,c) p[i][0]=parent[i][0];
    FOR (k,1,K-1) {
    	REP (i,c) {
    		if (p[i][k-1]!=-1) {
				p[i][k]=p[p[i][k-1]][k-1];
    		}
    	}
    }
}

int LCA_query(int a, int b) {
	if (depth[a] < depth[b]) swap(a,b);
	for (int k=K-1;k>=0;k--) {
		if (depth[a]-(1<<k)>=depth[b]) {
			a=p[a][k];
		}
	}
	if (a==b) return a;
	for (int k=K-1;k>=0;k--) {
		if (p[a][k]!=p[b][k]) {
			a=p[a][k];
			b=p[b][k];
		}
	}
	return parent[a][0];
}

int ok=1;
int direction[N];

void direct(int x, int z, int dir) {
	if (x==z) return;
	if (direction[x]==0) {
		direction[x]=dir;
		int y=parent[x][0], i=parent[x][1];
		int a=comp[edge[i][0]], b=comp[edge[i][1]];
		if (dir==-1) {
			if (a==x && b==y) label[i]='R'; else label[i]='L';
		} else {
			if (a==y && b==x) label[i]='R'; else label[i]='L';
		}
		direct(y, z, dir);
	} else {
		if (direction[x]!=dir) ok=0;
	}
}

int main() {
	scanf("%d %d",&n,&m);
	assert(n<=100000 && m<=100000);
	REP (i,m) {
		int a,b;
		scanf("%d %d",&a,&b);
		assert(1<=a && a<=n); assert(1<=b && b<=n);
		a--; b--;
		edge[i][0]=a; edge[i][1]=b;
		adj[a].push_back({b,i});
		adj[b].push_back({a,i});
	}
	INIT(ind,-1);
	REP (i,n) if (ind[i]==-1) {
		tarjan(i);
	}
	int c=0;
	INIT(comp,-1);
	INIT(v,0);
	REP (i,n) if (!v[i]) {
		components(i,c);
		c++;
	}
	REP (i,m) if (bridge[i]) {
		int ca=comp[edge[i][0]], cb=comp[edge[i][1]];
		//assert(ca!=cb);
		adjc[ca].push_back({cb,i});
		adjc[cb].push_back({ca,i});
	}
	INIT(depth,-1);
	REP (i,n) if (depth[i]==-1) {
		dfs(i);
	}
	LCA_init(c);
	REP (i,m) label[i]='B';
	label[m]=0;
	scanf("%d",&q);
	assert(q<=100000);
	vector<PII> ord;
	REP (i,q) {
		int a,b;
		scanf("%d %d",&a,&b);
		assert(1<=a && a<=n); assert(1<=b && b<=n);
		a--; b--;
		path[i][0]=comp[a]; path[i][1]=comp[b]; path[i][2]=LCA_query(comp[a], comp[b]);
		assert(path[i][2]!=-1);
		ord.push_back({depth[path[i][2]],i});
	}
	sort(ALL(ord));
	INIT(direction,0);
	for (PII di : ord) {
		int i=di.second;
		int a=path[i][0], b=path[i][1], l=path[i][2];
		direct(a,l,-1);
		direct(b,l,1);
	}
	printf("%s\n",label);
	assert(ok);
	return 0;
}

Compilation message

oneway.cpp: In function 'int main()':
oneway.cpp:142:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d",&n,&m);
                      ^
oneway.cpp:146:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d",&a,&b);
                       ^
oneway.cpp:177:16: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&q);
                ^
oneway.cpp:182:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d",&a,&b);
                       ^

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 19308 KB Output is correct
2 Correct 0 ms 19308 KB Output is correct
3 Correct 3 ms 19308 KB Output is correct
4 Correct 3 ms 19440 KB Output is correct
5 Correct 9 ms 19440 KB Output is correct
6 Correct 0 ms 19308 KB Output is correct
7 Correct 3 ms 19440 KB Output is correct
8 Correct 0 ms 19440 KB Output is correct
9 Correct 3 ms 19308 KB Output is correct
10 Correct 0 ms 19308 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 19308 KB Output is correct
2 Correct 0 ms 19308 KB Output is correct
3 Correct 3 ms 19308 KB Output is correct
4 Correct 3 ms 19440 KB Output is correct
5 Correct 9 ms 19440 KB Output is correct
6 Correct 0 ms 19308 KB Output is correct
7 Correct 3 ms 19440 KB Output is correct
8 Correct 0 ms 19440 KB Output is correct
9 Correct 3 ms 19308 KB Output is correct
10 Correct 0 ms 19308 KB Output is correct
11 Correct 49 ms 22912 KB Output is correct
12 Correct 86 ms 23512 KB Output is correct
13 Correct 93 ms 24220 KB Output is correct
14 Correct 109 ms 25068 KB Output is correct
15 Correct 143 ms 25592 KB Output is correct
16 Correct 136 ms 26832 KB Output is correct
17 Correct 149 ms 27680 KB Output is correct
18 Correct 139 ms 26832 KB Output is correct
19 Correct 133 ms 28584 KB Output is correct
20 Correct 69 ms 23000 KB Output is correct
21 Correct 79 ms 22792 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 19308 KB Output is correct
2 Correct 0 ms 19308 KB Output is correct
3 Correct 3 ms 19308 KB Output is correct
4 Correct 3 ms 19440 KB Output is correct
5 Correct 9 ms 19440 KB Output is correct
6 Correct 0 ms 19308 KB Output is correct
7 Correct 3 ms 19440 KB Output is correct
8 Correct 0 ms 19440 KB Output is correct
9 Correct 3 ms 19308 KB Output is correct
10 Correct 0 ms 19308 KB Output is correct
11 Correct 49 ms 22912 KB Output is correct
12 Correct 86 ms 23512 KB Output is correct
13 Correct 93 ms 24220 KB Output is correct
14 Correct 109 ms 25068 KB Output is correct
15 Correct 143 ms 25592 KB Output is correct
16 Correct 136 ms 26832 KB Output is correct
17 Correct 149 ms 27680 KB Output is correct
18 Correct 139 ms 26832 KB Output is correct
19 Correct 133 ms 28584 KB Output is correct
20 Correct 69 ms 23000 KB Output is correct
21 Correct 79 ms 22792 KB Output is correct
22 Correct 263 ms 29268 KB Output is correct
23 Correct 226 ms 28124 KB Output is correct
24 Correct 183 ms 28404 KB Output is correct
25 Correct 273 ms 31608 KB Output is correct
26 Correct 259 ms 28988 KB Output is correct
27 Correct 179 ms 28128 KB Output is correct
28 Correct 49 ms 23060 KB Output is correct
29 Correct 109 ms 24276 KB Output is correct
30 Correct 129 ms 24380 KB Output is correct
31 Correct 126 ms 24636 KB Output is correct
32 Correct 186 ms 26964 KB Output is correct