Submission #418073

#	Time	Username	Problem	Language	Result	Execution time	Memory
418073		JerryLiu06	Tug of War (BOI15_tug)	C++17	71 / 100	188 ms	4556 KiB

tug

#include <bits/stdc++.h>
 
using namespace std;
 
using ll = long long;
using ld = long double;
using db = double;
using str = string;
 
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
 
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
 
#define mp make_pair
#define f first
#define s second
 
#define sz(x) (int)(x).size()
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define sor(x) sort(all(x))
#define ft front()
#define bk back()
#define pb push_back
#define pf push_front
 
#define lb lower_bound
#define ub upper_bound
 
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define EACH(a,x) for (auto& a: x)
 
const int MOD = 1e9 + 7;
const int MX = 3e4 + 10;
const ll INF = 1e18;

int N, K; multiset<pi> adj[MX]; int inDeg[MX], tot; bool vis[MX]; vi todo;

void DFS(int X) {
    vis[X] = true; pi E = *adj[X].bg();

    tot += E.s; if (!vis[E.f]) { adj[X].clear(); adj[E.f].erase(adj[E.f].find({X, -E.s})); DFS(E.f); }
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(0);

    cin >> N >> K; F0R(i, 2 * N) { 
        int A, B, S; cin >> A >> B >> S; 
        
        adj[A].insert({N + B, S}), adj[N + B].insert({A, -S});
    }
    queue<int> Q; FOR(i, 1, 2 * N + 1) { 
        if (sz(adj[i]) == 0) { cout << "NO"; return 0; } 

        if (sz(adj[i]) == 1) Q.push(i);
    }
    while (!Q.empty()) {
        int cur = Q.front(); Q.pop(); if (sz(adj[cur]) == 0) { cout << "NO"; return 0; }

        pi E = *adj[cur].bg(); tot += E.s; adj[cur].clear(); adj[E.f].erase(adj[E.f].find({cur, -E.s}));

        if (sz(adj[E.f]) == 1) Q.push(E.f);
    }
    if (tot) todo.pb(abs(tot)); FOR(i, 1, 2 * N + 1) if (!vis[i] && sz(adj[i])) {
        tot = 0; adj[i].erase(adj[i].bg()); DFS(i); if (tot) todo.pb(abs(tot));
    }
    bitset<40 * MX> DP; DP[20 * MX] = 1;EACH(C, todo) DP = (DP << C) | (DP >> C); 

    FOR(i, 20 * MX - K, 20 * MX + K + 1) if (DP[i]) { cout << "YES"; return 0; } cout << "NO";
}

Compilation message (stderr)

tug.cpp: In function 'int main()':
tug.cpp:39:20: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   39 | #define FOR(i,a,b) for (int i = (a); i < (b); ++i)
      |                    ^~~
tug.cpp:82:5: note: in expansion of macro 'FOR'
   82 |     FOR(i, 20 * MX - K, 20 * MX + K + 1) if (DP[i]) { cout << "YES"; return 0; } cout << "NO";
      |     ^~~
tug.cpp:82:82: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   82 |     FOR(i, 20 * MX - K, 20 * MX + K + 1) if (DP[i]) { cout << "YES"; return 0; } cout << "NO";
      |                                                                                  ^~~~

• Subtask 1: 18 / 18
• Subtask 2: 30 / 30
• Subtask 3: 23 / 23
• Subtask 4: 0 / 29