//#pragma GCC optimize ("O3")
//#pragma GCC target ("sse4")
#include <bits/stdc++.h>
using namespace std;
template<class T> using min_heap = priority_queue<T, vector<T>, greater<T>>;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define F0R1(i, a) for (int i=1; i<=(a); i++)
#define FORd(i, a, b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i, a) for (int i = (a)-1; i >= 0; i--)
#define trav(a, x) for (auto& a : x)
#define MIN(a, b) a = min(a, b)
#define MAX(a, b) a = max(a, b)
#define INF 1000000010
#define LL_INF 4500000000000000000LL
#define LSOne(S) (S & (-S))
#define EPS 1e-9
#define pA first
#define pB second
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define PI acos(-1.0)
// #define MOD (int)(2e+9+11)
#define MOD (int)(1e+9+7)
#define SET(vec, val, size) for (int i = 0; i < size; i++) vec[i] = val;
#define SET2D(arr, val, dim1, dim2) F0R(i, dim1) F0R(j, dim2) arr[i][j] = val;
#define SET3D(arr, val, dim1, dim2, dim3) F0R(i, dim1) F0R(j, dim2) F0R(k, dim3) arr[i][j][k] = val;
#define SET4D(arr, val, dim1, dim2, dim3, dim4) F0R(i, dim1) F0R(j, dim2) F0R(k, dim3) F0R(l, dim4) arr[i][j][k][l] = val;
#define lb lower_bound
#define ub upper_bound
#define sz(x) (int)x.size()
#define beg(x) x.begin()
#define en(x) x.end()
#define all(x) beg(x), en(x)
#define resz resize
#define SORT(vec) sort(all(vec))
#define RSORT(vec) sort(vec.rbegin(),vec.rend())
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vl;
// @formatter:off
// Source: Benq (https://github.com/bqi343/USACO) [Modified]
namespace input {
template<class T> void re(complex<T>& x);
template<class T1, class T2> void re(pair<T1,T2>& p);
template<class T> void re(vector<T>& a);
template<class T, size_t SZ> void re(array<T,SZ>& a);
template<class T> void reA(T A[], int sz);
template<class T> void re(T& x) { cin >> x; }
void re(double& x) { string t; re(t); x = stod(t); }
void re(ld& x) { string t; re(t); x = stold(t); }
template<class Arg, class... Args> void re(Arg& first, Args&... rest) {
re(first); re(rest...);
}
template<class T1, class T2> void re(pair<T1,T2>& p) { re(p.pA,p.pB); }
template<class T> void re(vector<T>& a) { F0R(i,sz(a)) re(a[i]); }
template<class T, size_t SZ> void re(array<T,SZ>& a) { F0R(i,SZ) re(a[i]); }
template<class T> void reA(T A[], int sz) { F0R(i, sz) re(A[i]); }
void setupIO(const string &PROB = "") {
ios::sync_with_stdio(false);
cin.tie(nullptr);
if (PROB.length() != 0) {
ifstream infile(PROB + ".in");
if (infile.good()) {
freopen((PROB + ".in").c_str(), "r", stdin);
freopen((PROB + ".out").c_str(), "w", stdout);
}
}
}
}
using namespace input;
namespace output {
template<class T1, class T2> void prD(const pair<T1,T2>& x);
template<class T, size_t SZ> void prD(const array<T,SZ>& x);
template<class T> void prD(const vector<T>& x);
template<class T> void prD(const set<T>& x);
template<class T1, class T2> void prD(const map<T1,T2>& x);
template<class T1, class T2> void pr(const pair<T1,T2>& x);
template<class T, size_t SZ> void pr(const array<T,SZ>& x);
template<class T> void pr(const vector<T>& x);
template<class T> void pr(const set<T>& x);
template<class T1, class T2> void pr(const map<T1,T2>& x);
template<class T> void prD(const T& x) { cout << x; }
template<class Arg, class... Args> void prD(const Arg& first, const Args&... rest) {
prD(first); prD(rest...);
}
template<class T1, class T2> void prD(const pair<T1,T2>& x) {
prD("{",x.pA,", ",x.pB,"}");
}
template<class T> void prDContain(const T& x) {
prD("{");
bool fst = 1; for (const auto& a: x) prD(!fst?", ":"",a), fst = 0; // const needed for vector<bool>
prD("}");
}
template<class T, size_t SZ> void prD(const array<T,SZ>& x) { prDContain(x); }
template<class T> void prD(const vector<T>& x) { prDContain(x); }
template<class T> void prD(const set<T>& x) { prDContain(x); }
template<class T1, class T2> void prD(const map<T1,T2>& x) { prDContain(x); }
void psD() { prD("\n"); }
template<class Arg> void psD(const Arg& first) {
prD(first); psD(); // no space at end of line
}
template<class Arg, class... Args> void psD(const Arg& first, const Args&... rest) {
prD(first," "); psD(rest...); // print w/ spaces
}
template<class T> void pr(const T& x) { cout << x; }
template<class Arg, class... Args> void pr(const Arg& first, const Args&... rest) {
pr(first); pr(rest...);
}
template<class T1, class T2> void pr(const pair<T1,T2>& x) {
pr(x.pA, " ", x.pB);
}
template<class T> void prContain(const T& x) {
bool fst = 1; for (const auto& a: x) pr(!fst?" ":"",a), fst = 0; // const needed for vector<bool>
}
template<class T, size_t SZ> void pr(const array<T,SZ>& x) { prContain(x); }
template<class T> void pr(const vector<T>& x) { prContain(x); }
template<class T> void pr(const set<T>& x) { prContain(x); }
template<class T1, class T2> void pr(const map<T1,T2>& x) { prContain(x); }
void ps() { pr("\n"); }
template<class Arg> void ps(const Arg& first) {
pr(first); ps(); // no space at end of line
}
template<class Arg, class... Args> void ps(const Arg& first, const Args&... rest) {
pr(first," "); ps(rest...); // print w/ spaces
}
}
using namespace output;
// @formatter:on
/* ============================ */
int n, m;
set<ii> bridge, bridge2;
set<int> dc, dc2;
int getFarthest(int a) {
if (a <= n) {
return *dc.lb(a);
} else {
auto it = dc2.ub(a);
int farthest;
if (it == dc2.begin()) {
farthest = n + 1;
} else {
it--;
farthest = *it;
}
return farthest;
}
}
bool canReach(int a, int b, int flipCt) {
if (flipCt > 2) return false;
if (a <= n && b <= n) {
if (a <= b) return b <= getFarthest(a);
int farthest = getFarthest(a);
auto it2 = bridge.lb({ a, -1 });
if (it2 == bridge.end()) return false;
if (it2->pA > farthest) return false;
return canReach(it2->pB, b, flipCt + 1);
} else if (a > n && b > n) {
if (a >= b) return b >= getFarthest(a);
auto it2 = bridge2.ub({ a, 2*INF });
if (it2 == bridge2.begin()) return false;
it2--;
if (it2->pA < getFarthest(a)) return false;
return canReach(it2->pB, b, flipCt + 1);
} else {
if (sz(bridge) == 0) return false;
if (a <= n) {
int farthest = getFarthest(a);
bool op1 = false;
auto it2 = bridge2.lb({ b, -1 });
if (it2 != bridge2.end() && !(it2->pB > farthest || it2->pB < a)) op1 = canReach(it2->pA, b, flipCt + 1);
if (op1) return true;
it2 = bridge.lb({ a, -1 });
if (it2 == bridge.end()) return false;
if (it2->pA > farthest) return false;
return canReach(it2->pB, b, flipCt + 1);
} else {
auto it = dc2.ub(a);
int farthest = getFarthest(a);
bool op1 = false;
auto it2 = bridge.lb({ b, 2*INF });
if (it2 == bridge.begin()) {}
else {
it2--;
if (it2->pB < farthest || it2->pB > a) {}
else op1 = canReach(it2->pA, b, flipCt + 1);
}
if (op1) return true;
it2 = bridge2.lb({ a, 2*INF });
if (it2 == bridge2.begin()) return false;
it2--;
if (it2->pA < farthest) return false;
return canReach(it2->pB, b, flipCt + 1);
}
}
}
int main() {
setupIO();
re(n, m);
dc.insert(n);
F0R(i, m) {
char c; int a, b; re(c, a, b);
if (c == 'A') {
if (a > b) {
tie(a, b) = mt(b, a);
}
bridge.insert({a, b});
bridge2.insert({b, a});
} else if (c == 'B') {
if (a <= n) {
if (a > b) {
tie(a, b) = mt(b, a);
}
dc.insert(a);
} else {
if (a < b) {
tie(a, b) = mt(b, a);
}
dc2.insert(a);
}
} else {
if (canReach(a, b, 0)) {
ps("DA");
} else {
ps("NE");
}
}
}
return 0;
}
Compilation message
mostovi.cpp: In function 'bool canReach(int, int, int)':
mostovi.cpp:213:18: warning: variable 'it' set but not used [-Wunused-but-set-variable]
auto it = dc2.ub(a);
^~
mostovi.cpp: In function 'void input::setupIO(const string&)':
mostovi.cpp:84:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
freopen((PROB + ".in").c_str(), "r", stdin);
~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mostovi.cpp:85:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
freopen((PROB + ".out").c_str(), "w", stdout);
~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
2 ms |
376 KB |
Output is correct |
| 2 |
Correct |
2 ms |
376 KB |
Output is correct |
| 3 |
Correct |
3 ms |
376 KB |
Output is correct |
| 4 |
Correct |
3 ms |
376 KB |
Output is correct |
| 5 |
Correct |
3 ms |
376 KB |
Output is correct |
| 6 |
Correct |
2 ms |
376 KB |
Output is correct |
| 7 |
Correct |
216 ms |
7712 KB |
Output is correct |
| 8 |
Correct |
241 ms |
7776 KB |
Output is correct |
| 9 |
Correct |
216 ms |
7672 KB |
Output is correct |
| 10 |
Correct |
264 ms |
9976 KB |
Output is correct |
