Submission #369356

#	Time	Username	Problem	Language	Result	Execution time	Memory
369356		ACmachine	Tug of War (BOI15_tug)	C++17	23 / 100	111 ms	19112 KiB

tug

#include <bits/stdc++.h>
using namespace std;

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;

typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<str> vstr;

#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back 
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define rsz resize 
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)
	
const double EPS = 1e-9;
const int MOD = 1e9+7; // 998244353;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};

#ifdef DEBUG
#define DBG if(1)
#else
#define DBG if(0)
#endif

#define dbg(x) cout << "(" << #x << " : " << x << ")" << endl;
// ostreams
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "[";  REP(i, v.size()) out << v[i] << ", ";  out << "]"; return out;}
// istreams
template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }
template<class T, class U>
istream& operator>>(istream& in, pair<T, U> &p){ in >> p.ff >> p.ss; return in; }
//searches
template<typename T, typename U>
T bsl(T lo, T hi, U f){ hi++; T mid; while(lo < hi){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid+1; } return lo; }
template<typename U>
double bsld(double lo, double hi, U f, double p = 1e-9){ int r = 3 + (int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid; } return (lo + hi)/2; }
template<typename T, typename U>
T bsh(T lo, T hi, U f){ lo--; T mid; while(lo < hi){ mid = (lo + hi + 1)/2; f(mid) ? lo = mid : hi = mid-1; } return lo; }
template<typename U>
double bshd(double lo, double hi, U f, double p = 1e-9){ int r = 3+(int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? lo = mid : hi = mid; } return (lo + hi)/2; }
// some more utility functions
template<typename T>
pair<T, int> get_min(vector<T> &v){ typename vector<T> :: iterator it = min_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T>
pair<T, int> get_max(vector<T> &v){ typename vector<T> :: iterator it = max_element(v.begin(), v.end()); return mp(*it, it - v.begin());}        
template<typename T> bool ckmin(T& a, const T& b){return b < a ? a = b , true : false;}
template<typename T> bool ckmax(T& a, const T& b){return b > a ? a = b, true : false;}

    
int main(){
 	ios_base::sync_with_stdio(false);
 	cin.tie(NULL); cout.tie(NULL);
	int n, k; cin >> n >> k;
    vector<vector<array<int, 2>>> g(2 * n);
    vector<array<int, 3>> edges;
    vector<int> deg(2 * n, 0);
    REP(i, 2 * n){
        int l, r, s;
        cin >> l >> r >> s;
        l--; r--;
        g[l].pb({r + n, s});
        g[r + n].pb({l, s});
        edges.pb({l, r + n, s});
        deg[l]++;
        deg[r + n]++;
    }
    vector<int> component_id(2 * n, -1);
    function<void(int, int)> dfs_comp = [&](int v, int id){
        component_id[v] = id;
        for(auto x : g[v]){
            if(component_id[x[0]] == -1) 
                dfs_comp(x[0], id);
        }
    };
    int curr_id = 0;
    REP(i, 2 * n){
        if(component_id[i] == -1){
            dfs_comp(i, curr_id);
            curr_id++;
        }
    }
    vector<int> vertex_count(2 * n, 0);
    vector<int> edge_count(2 * n, 0);
    REP(i, 2 * n) vertex_count[component_id[i]]++;
    REP(i, edges.size()) edge_count[component_id[edges[i][0]]]++;
    bool can = true;
    REP(i, 2 * n){
        if(vertex_count[i] == (edge_count[i] - 1))
            can = false;
    }
    if(!can){
        cout << "NO" << "\n";
        return 0;
    }
    int difference = 0; // rsum - lsum
    set<array<int, 3>> used_edges;
    queue<int> q;
    vector<bool> processed(2 * n, false);
    REP(i, 2 * n){
        if(deg[i] == 1) 
            q.push(i);
    } 
    while(!q.empty()){
        int v = q.front();
        q.pop();
        for(auto x : g[v]){
            int sr = v; 
            int ds = x[0];
            int w = x[1];
            if(sr > ds) swap(sr, ds);
            if(used_edges.find({sr, ds, w}) == used_edges.end()){
                used_edges.insert({sr, ds, w});
                processed[v] = true;
                if(v >= n) difference += w;
                else difference -= w;
                deg[x[0]]--;
                if(deg[x[0]] == 1){
                    q.push(x[0]);
                }
            }
        }
    }
    vector<int> knapsack_values;
    function<void(int, int&, int&)> dfs = [&](int v, int& A, int& B){
        processed[v] =true;
        for(auto x : g[v]){
            int sr = v;
            int ds = x[0];
            int w = x[1];
            if(sr > ds) swap(sr, ds);
            if(used_edges.find({sr, ds, w}) == used_edges.end()){
                used_edges.insert({sr, ds, w});
                if(v >= n) A += w;
                else A -= w;
                if(x[0] >= n) B += w;
                else B -= w;
                dfs(x[0], A, B);
            }
        }
    };
    REP(i, 2 * n){
        if(!processed[i]){
            //cycle -> get 2 values, A and B
            int A = 0, B = 0;
            dfs(i, A, B);
            if(A > B) swap(A, B);
            difference += A; 
            knapsack_values.pb(B - A);
        }
    }
    vector<int> new_knapsack_values;
    vector<int> cnt(2e6, 0);
    for(auto val : knapsack_values) cnt[val]++;
    REP(i, 2e6){
        if(cnt[i] == 0) continue;
        int df = (cnt[i] - 1) / 2;
        cnt[i] -= df * 2;
        cnt[2 * i] += df;
    }
    REP(i, 2e6){
        REP(j, cnt[i])
            new_knapsack_values.pb(i);
    }
    const int mx = 2e6+5;
	vector<int> dp(mx, 0);
    dp[0] = 1;
    for(int val : new_knapsack_values){
        REPD(i, mx - 2){
            if(i - val < 0) break;
            if(dp[i - val]) dp[i] = 1; 
        }
    }
    REP(i, mx){
        if(dp[i] == 1 && abs(difference + i) <= k){
            cout << "YES" << "\n";
            return 0;
        }
    }
    cout << "NO" << "\n";
    return 0;
}

Compilation message (stderr)

tug.cpp: In function 'int main()':
tug.cpp:26:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 | #define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
      |                                        ^
tug.cpp:28:18: note: in expansion of macro 'FOR'
   28 | #define REP(i,b) FOR(i,0,b,1)
      |                  ^~~
tug.cpp:120:5: note: in expansion of macro 'REP'
  120 |     REP(i, edges.size()) edge_count[component_id[edges[i][0]]]++;
      |     ^~~

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