Submission #331298

#	Time	Username	Problem	Language	Result	Execution time	Memory
331298		ec1117	Race (IOI11_race)	C++17	0 / 100	13 ms	19180 KiB

race

#include "bits/stdc++.h"

using namespace std;
 
typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str; 

typedef pair<int,int> pi;
typedef pair<pi, int> pii;
typedef pair<ll,ll> pl; 
typedef pair<db,db> pd; 

typedef vector<int> vi; 
typedef vector<bool> vb; 
typedef vector<ll> vl; 
typedef vector<db> vd; 
typedef vector<str> vs; 
typedef vector<pi> vpi;
typedef vector<pl> vpl; 
typedef vector<pd> vpd; 
template<class T> using V = vector<T>; 
template<class T, size_t SZ> using AR = array<T,SZ>; 

#define mp make_pair
#define f first
#define s second
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend() 
#define sor(x) sort(all(x)) 
#define rsz resize
#define ins insert 
#define ft front() 
#define bk back()
#define pf push_front 
#define pb push_back
#define eb emplace_back 
#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 For(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 Rof(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)

template<class T> bool ckmin(T& a, const T& b) { 
        return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { 
        return a < b ? a = b, 1 : 0; } 
constexpr int pct(int x) { return __builtin_popcount(x); } 
constexpr int bits(int x) { return 31-__builtin_clz(x); } // floor(log2(x)) 
ll cdiv(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up
ll fdiv(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down
ll half(ll x) { return fdiv(x,2); }

template<class T, class U> T fstTrue(T lo, T hi, U f) { 
        // note: if (lo+hi)/2 is used instead of half(lo+hi) then this will loop infinitely when lo=hi
        hi ++; assert(lo <= hi); // assuming f is increasing
        while (lo < hi) { // find first index such that f is true 
                T mid = half(lo+hi);
                f(mid) ? hi = mid : lo = mid+1; 
        } 
        return lo;
}
template<class T, class U> T lstTrue(T lo, T hi, U f) {
        lo --; assert(lo <= hi); // assuming f is decreasing
        while (lo < hi) { // find first index such that f is true 
                T mid = half(lo+hi+1);
                f(mid) ? lo = mid : hi = mid-1;
        } 
        return lo;
}
template<class T> void remDup(vector<T>& v) { 
        sort(all(v)); v.erase(unique(all(v)),end(v)); }

// INPUT
template<class A> void re(complex<A>& c);
template<class A, class B> void re(pair<A,B>& p);
template<class A> void re(vector<A>& v);
template<class A, size_t SZ> void re(array<A,SZ>& a);

template<class T> void re(T& x) { cin >> x; }
void re(db& d) { str t; re(t); d = stod(t); }
void re(ld& d) { str t; re(t); d = stold(t); }
template<class H, class... T> void re(H& h, T&... t) { re(h); re(t...); }

template<class A> void re(complex<A>& c) { A a,b; re(a,b); c = {a,b}; }
template<class A, class B> void re(pair<A,B>& p) { re(p.f,p.s); }
template<class A> void re(vector<A>& x) { trav(a,x) re(a); }
template<class A, size_t SZ> void re(array<A,SZ>& x) { trav(a,x) re(a); }

// TO_STRING
#define ts to_string
str ts(char c) { return str(1,c); }
str ts(const char* s) { return (str)s; }
str ts(str s) { return s; }
str ts(bool b) { 
        #ifdef LOCAL
                return b ? "true" : "false"; 
        #else 
                return ts((int)b);
        #endif
}
template<class A> str ts(complex<A> c) { 
        stringstream ss; ss << c; return ss.str(); }
str ts(vector<bool> v) {
        str res = "{"; F0R(i,sz(v)) res += char('0'+v[i]);
        res += "}"; return res; }
template<size_t SZ> str ts(bitset<SZ> b) {
        str res = ""; F0R(i,SZ) res += char('0'+b[i]);
        return res; }
template<class A, class B> str ts(pair<A,B> p);
template<class T> str ts(T v) { // containers with begin(), end()
        #ifdef LOCAL
                bool fst = 1; str res = "{";
                for (const auto& x: v) {
                        if (!fst) res += ", ";
                        fst = 0; res += ts(x);
                }
                res += "}"; return res;
        #else
                bool fst = 1; str res = "";
                for (const auto& x: v) {
                        if (!fst) res += " ";
                        fst = 0; res += ts(x);
                }
                return res;

        #endif
}
template<class A, class B> str ts(pair<A,B> p) {
        #ifdef LOCAL
                return "("+ts(p.f)+", "+ts(p.s)+")"; 
        #else
                return ts(p.f)+" "+ts(p.s);
        #endif
}

// OUTPUT
template<class A> void pr(A x) { cout << ts(x); }
template<class H, class... T> void pr(const H& h, const T&... t) { 
        pr(h); pr(t...); }
void ps() { pr("\n"); } // print w/ spaces
template<class H, class... T> void ps(const H& h, const T&... t) { 
        pr(h); if (sizeof...(t)) pr(" "); ps(t...); }

// DEBUG
void DBG() { cerr << "]" << endl; }
template<class H, class... T> void DBG(H h, T... t) {
        cerr << ts(h); if (sizeof...(t)) cerr << ", ";
        DBG(t...); }
#ifdef LOCAL // compile with -DLOCAL, chk -> fake assert
        #define dbg(...) cerr << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
        #define chk(...) if (!(__VA_ARGS__)) cerr << "Line(" << __LINE__ << ") -> function(" \
                 << __FUNCTION__  << ") -> CHK FAILED: (" << #__VA_ARGS__ << ")" << "\n", exit(0);
#else
        #define dbg(...) 0
        #define chk(...) 0
#endif

int gcd(int a, int b) {if (b == 0)return a;return gcd(b, a % b);}
int max(int a,int b, int c){return max(a,max(b,c));}
int min(int a,int b, int c){return min(a,min(b,c));}
ll max(ll a,ll b, ll c){return max(a,max(b,c));}
ll min(ll a,ll b, ll c){return min(a,min(b,c));}
void dbga(int arr[], int n){vi v;For(i,n)v.pb(arr[i]);dbg(v);}
void dbga(ll arr[], int n){vi v;For(i,n)v.pb(arr[i]);dbg(v);}

// FILE I/O
void setIn(str s) { freopen(s.c_str(),"r",stdin); }
void setOut(str s) { freopen(s.c_str(),"w",stdout); }
void unsyncIO() { cin.tie(0)->sync_with_stdio(0); }
void setIO(str s = "") {
        unsyncIO();
        // cin.exceptions(cin.failbit); 
        // throws exception when do smth illegal
        // ex. try to read letter into int
        if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
}
// 576743 29995400689069LL
const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5;
const ll INF = 1e18;
const ld PI = acos((ld)-1);
const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1};
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count());

int k, sub[MX], h[MX][2];
ll mn=MOD;
set<pi> adj[MX];
vpl d;
map<ll,ll> b[MX];


void dfs1(int n, int p){
    sub[n]=1;
    trav(x,adj[n]){
        if(x.f==p)continue;
        dfs1(x.f,n);
        sub[n]+=sub[x.f];
    }
}

int centroid(int n, int p, int tot){//is this right?
    trav(x,adj[n]){
        if(x.f==p)continue;
        if(sub[x.f]*2>tot)return centroid(x.f,n,tot);
    }
    return n;
}

void dfs2(int n, int p, ll ne, ll dist, int c){
    if(dist==k)ckmin(mn,ne);
    if(b[c][k-dist])ckmin(mn,ne+b[c][k-dist]);
    d.pb(mp(dist,ne));
    trav(x,adj[n]){
        if(x.f==p)continue;
        dfs2(x.f,n,ne+1,dist+x.s,c);
    }
}

void solve(int n){
    dfs1(n,n);
    int c=centroid(n,n,sub[n]);
    trav(x,adj[c]){
        d.clear();
        dfs2(x.f,n,0,0,c);
        trav(y,d){
            if(b[c][y.f])ckmin(b[c][y.f],y.s);
            else b[c][y.f]=y.s;
        }
    }
    trav(x,adj[c]){
        pi tmp=*adj[x.f].lb(mp(c,0));
        assert(tmp.f==c);
        adj[x.f].erase(tmp);
        solve(x.f);
    }
}

int best_path(int n, int K, int h[][2],int l[]){
    k=K;
    For(i,n-1){
        adj[h[i][0]].ins(mp(h[i][1],l[i]));
        adj[h[i][1]].ins(mp(h[i][0],l[i]));
    }

    solve(0);
    if(mn==MOD)return -1;
    else return mn;

}
//psums, bsearch, two pointers
/* stuff you should look for
        * int overflow, array bounds
        * special cases (n=1?)
        * think of simple solution first
        * do smth instead of nothing and stay organized
        * WRITE STUFF DOWN
        * DON'T GET STUCK ON ONE APPROACH
*/

// int centroid(int x) {
//     dfs(x,-1); 
//     for (int sz = sub[x];;) {
//         pi mx = {0,0};
//         trav(y,adj[x]) if (!done[y] && sub[y] < sub[x]) 
//             ckmax(mx,{sub[y],y});
//         if (mx.f*2 <= sz) return x; 
//         x = mx.s;
//     }
// }

Compilation message (stderr)

race.cpp: In function 'void dbga(int*, int)':
race.cpp:163:26: warning: statement has no effect [-Wunused-value]
  163 |         #define dbg(...) 0
      |                          ^
race.cpp:172:55: note: in expansion of macro 'dbg'
  172 | void dbga(int arr[], int n){vi v;For(i,n)v.pb(arr[i]);dbg(v);}
      |                                                       ^~~
race.cpp: In function 'void dbga(ll*, int)':
race.cpp:163:26: warning: statement has no effect [-Wunused-value]
  163 |         #define dbg(...) 0
      |                          ^
race.cpp:173:54: note: in expansion of macro 'dbg'
  173 | void dbga(ll arr[], int n){vi v;For(i,n)v.pb(arr[i]);dbg(v);}
      |                                                      ^~~
race.cpp: In function 'void setIn(str)':
race.cpp:176:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  176 | void setIn(str s) { freopen(s.c_str(),"r",stdin); }
      |                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
race.cpp: In function 'void setOut(str)':
race.cpp:177:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  177 | void setOut(str s) { freopen(s.c_str(),"w",stdout); }
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57