Submission #1022919

#	Time	Username	Problem	Language	Result	Execution time	Memory
1022919		yeediot	Tug of War (BOI15_tug)	C++17	100 / 100	240 ms	12124 KiB

tug

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define pb push_back
#define sz(x) (int)(x.size())
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
#define vi vector<int>
#define vp vector<pii>
#define vvi vector<vi>
#define ykh mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count())
#define __lg(x) 63-__builtin_clzll(x)
#define pow2(x) (1LL<<x)
void __print(int x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef local
void CHECK();
void setio(){
    freopen("/Users/iantsai/cpp/input.txt","r",stdin);
    freopen("/Users/iantsai/cpp/output.txt","w",stdout);
}
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
void setio(){}
#define debug(x...)
#endif
#define TOI_is_so_de ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);setio();
const int mxn = 3e4 + 5;
int n, k, sum = 0, cur = 0;
multiset<pii>adj[2 * mxn];
bool vis[2 * mxn];
void solve(){
    cin >> n >> k;
    for(int i = 1; i <= 2 * n; i++){
        int l, r, s;
        cin >> l >> r >> s;
        r += n;
        adj[l].insert({r, s});
        adj[r].insert({l, -s});
    }
    queue<int>q;
    for(int i = 1; i <= 2 * n; i++){
        if(sz(adj[i]) == 0){
            cout << "NO\n";
            return;
        }
        else if(sz(adj[i]) == 1){
            q.push(i);
        }
    }
    while(sz(q)){
        auto v = q.front();
        q.pop();
        vis[v] = 1;
        auto [u, c] = *adj[v].begin();
        cur += c;
        adj[u].erase(adj[u].find({v, -c}));
        adj[v].clear();
        if(sz(adj[u]) == 1) q.push(u);
    }
    vector<int>val;
    val.pb(abs(cur));
    bitset<mxn * 10>bs;
    for(int i = 1; i <= 2 * n; i++){
        if(vis[i]) continue;
        cur = 0;
        int v = i;
        adj[i].erase(adj[i].begin());
        vis[v] = 1;
        do{
            auto [u, c] = *adj[v].begin();
            vis[u] = 1;
            adj[v].erase(adj[v].begin());
            cur += c;
            debug(cur);
            if(u != i)adj[u].erase(adj[u].find({v, -c}));
            v = u;
        }while(v != i);
        val.pb(abs(cur));
    }
    bs[0] = 1;
    debug(val);
    for(auto x : val){
        bs |= bs << x;
        sum += x;
    }
    for(int i = 0; i <= sum; i++){
        //debug(i, (bool)bs[i]);
        if(bs[i] and abs(sum - 2 * i) <= k){
            cout << "YES\n";
            return;
        }
    }
    cout <<"NO\n";
    return ;
}
signed main(){
    TOI_is_so_de;
    int t = 1;
    //cin >> t;
    while(t--){
        solve();
    }
    #ifdef local
    CHECK();
    #endif
}
/*
input:
 
*/
#ifdef local
void CHECK(){
    cerr << "\n[Time]: " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms.\n";
    function<bool(string,string)> compareFiles = [](string p1, string p2)->bool {
        std::ifstream file1(p1);
        std::ifstream file2(p2);
        if(!file1.is_open() || !file2.is_open()) return false;
        std::string line1, line2;
        while (getline(file1, line1) && getline(file2, line2)) {
            if (line1 != line2)return false;
        }
        int cnta = 0, cntb = 0;
        while(getline(file1,line1))cnta++;
        while(getline(file2,line2))cntb++;
        return cntb - cnta <= 1;
    };
    bool check = compareFiles("output.txt","expected.txt");
    if(check) cerr<<"ACCEPTED\n";
    else cerr<<"WRONG ANSWER!\n";
}
#else
#endif

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