답안 #499341

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
499341 2021-12-28T03:53:48 Z kaxzert One-Way Streets (CEOI17_oneway) C++17
0 / 100
2 ms 4940 KB
/**
      00  00      11      00  00  111111  00000  111111  000000
      00 00      1111      0000      11   00     11  11  000000
      0000      11  11      00      11    00000  111111    00
      00 00    11111111    0000    11     00     11 11     00
      00  00  11      11  00  00  111111  00000  11  11    00
**/

#include<bits/stdc++.h>

using namespace std;

#define fto(i, a, b) for(int i = a; i <= b; ++i)
#define fdto(i, a, b) for(int i = a; i >= b; --i)
#define bugarr(a, i, j) cout << #a << "{" << i << "..." << j << "}:"; fto(k, i, j-1) cout << a[k] << ", "; cout << a[j] << endl;
#define ll long long
#define db double
#define ldb long double
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define vt vector
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define trav(i, a) for(auto &i : a)
#define sz(a) (int)a.size()
#define pi(a, b) pair<a, b>
#define fast ios::sync_with_stdio(false); cin.tie(0)

void setIO(string s) {
    if (sz(s) != 0) {
        freopen((s+".inp").c_str(),"r",stdin);
        freopen((s+".out").c_str(),"w",stdout);
    }
}

void setIOusaco(string s) {
    if (sz(s) != 0) {
        freopen((s+".in").c_str(),"r",stdin);
        freopen((s+".out").c_str(),"w",stdout);
    }
}

template<typename T, typename V>
bool ckmin(T &a, V b) {return (b < a)? a = b, true : false;}
template<typename T, typename V>
bool ckmax(T &a, V b) {return (b > a)? a = b, true : false;}

void print(int x) {cout << x;}
void print(long long x) {cout << x;}
void print(unsigned x) {cout << x;}
void print(unsigned long long x) {cout << x;}
void print(double x) {cout << fixed << x;}
void print(long double x) {cout << fixed << x;}
void print(char x) {cout << "'" << x << "'";}
void print(string x) {cout << '"' << x << '"';}
void print(bool x) {cout << (x ? "true" : "false");}

template<typename T, typename V>
void print(const pair<T, V> &x) {cout << '{'; print(x.ff); cout << ", "; print(x.ss); cout << '}';}
template<typename T>
void print(const T &x) {int f = 0; cout << '{'; for (auto &i: x) cout << (f++ ? ", " : ""), print(i); cout << "}";}
void _print() {cout << "]" << endl;}
template <typename T, typename... V>
void _print(T t, V... v) {print(t); if (sizeof...(v)) cout << ", "; _print(v...);}

#ifdef TAP
#define bug(x...) cout << "[" << #x << "] = ["; _print(x)
#else
#define bug(x...) 
#endif

const int maxN = 200008;
int p[maxN], low[maxN], num[maxN], cnt, type[maxN], depth[maxN], out[maxN], in[maxN];
vt<int> ke[maxN];

int findset(int i) {
	return (p[i] == i ? i : p[i] = findset(p[i]));
}

void unionset(int con, int cha) {
	p[findset(con)] = findset(cha);
}

void dfs(int u, int p = 0) {
	num[u] = low[u] = ++cnt;
	int path = 0;
	trav(v, ke[u]) {
		if (v == p && path == 0) {
			++path;
			continue;
		}
		if (num[v] == 0) {
			dfs(v, u);
			if (ckmin(low[u], low[v])) unionset(u, v);
		} else {
			if (ckmin(low[u], num[v])) unionset(u, v);
		}
	}
}

void dfs2(int u) {
	num[u] = 1;
	type[u] += out[u];
	type[u] -= in[u];
	trav(v, ke[u]) {
		if (num[v] != 0) continue;
		depth[v] = depth[u]+(findset(u) != findset(v));
		dfs2(v);
		type[u] += out[v];
		type[u] -= in[v];
	}
}

int main() {
    #ifndef TAP 
    setIO("");
    //setIOusaco("CEOI17_oneway");
    #endif

    fast;
    int n, m;
    cin >> n >> m;
    vt<pi(int, int)> canh;
    fto(i, 1, m) {
    	int u, v;
    	cin >> u >> v;
    	ke[u].pb(v);
    	ke[v].pb(u);
    	canh.pb({u, v});
    }
    fto(i, 1, n) p[i] = i;

    fto(i, 1, n) {
    	if (num[i] == 0) {
    		dfs(i);
    		num[i] = 0;
    	}
    }

    int q;
    cin >> q;
    fto(i, 1, q) {
    	int u, v;
    	cin >> u >> v;
    	out[u]++;
    	in[v]++;
    }

    fto(i, 1, n) num[i] = 0;

    fto(i, 1, n) {
    	if (num[i] == 0) dfs2(i);
    }

    trav(u, canh) {
    	if (findset(u.ff) == findset(u.ss)) {
    		cout << 'B';
    		continue;
    	}
    	int haveswap = 0;
    	//bug(u.ff, u.ss, depth[u.ff], depth[u.ss]);
    	if (depth[u.ff] < depth[u.ss]) {
    		haveswap = 1;
    		swap(u.ff, u.ss);
    	}
    	//bug(type[u.ff], haveswap);
    	if (type[u.ff] == 0) cout << 'B';
    	if (type[u.ff] > 0) cout << (haveswap ? 'L' : 'R');
    	if (type[u.ff] < 0) cout << (haveswap ? 'R' : 'L');
    }
    cout << '\n';

    return 0;
}

Compilation message

oneway.cpp: In function 'void setIO(std::string)':
oneway.cpp:34:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |         freopen((s+".inp").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
oneway.cpp:35:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |         freopen((s+".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
oneway.cpp: In function 'void setIOusaco(std::string)':
oneway.cpp:41:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |         freopen((s+".in").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
oneway.cpp:42:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |         freopen((s+".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# 결과 실행 시간 메모리 Grader output
1 Incorrect 2 ms 4940 KB Output isn't correct
2 Halted 0 ms 0 KB -
# 결과 실행 시간 메모리 Grader output
1 Incorrect 2 ms 4940 KB Output isn't correct
2 Halted 0 ms 0 KB -
# 결과 실행 시간 메모리 Grader output
1 Incorrect 2 ms 4940 KB Output isn't correct
2 Halted 0 ms 0 KB -