Submission #3949308


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

#define NDEBUG
#ifdef DEBUG
#include "../cout11.h"
#undef NDEBUG
#endif
#include <cassert>

#ifdef DEBUG
#define debug(fmt, ...) fprintf(stderr, fmt, __VA_ARGS__)
#else
#define debug(fmt, ...)
#endif

typedef long long ll;
typedef long double Double;
typedef unsigned long long ull;
typedef pair<int,int> ii;
typedef pair<ll,ll> llll;
typedef pair<double,double> dd;

typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<ii> vii;
typedef vector<vector<ii>> vvii;
typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<llll> vllll;
typedef vector<bool> vb;
typedef vector<string> vs;
typedef vector<double> vd;
typedef vector<long double> vD;

#define sz(a)  int((a).size())
#define pb  push_back
#define eb  emplace_back
#define FOR(var,from,to) for(int var=(from);var<=(to);++var)
#define rep(var,n)  for(int var=0;var<(n);++var)
#define rep1(var,n)  for(int var=1;var<=(n);++var)
#define repC2(vari,varj,n)  for(int vari=0;vari<(n)-1;++vari)for(int varj=vari+1;varj<(n);++varj)
#define repC3(vari,varj,vark,n)  for(int vari=0;vari<(n)-2;++vari)for(int varj=vari+1;varj<(n)-1;++varj)for(int vark=varj+1;vark<(n);++vark)
#define ALL(c)  (c).begin(),(c).end()
#define RALL(c)  (c).rbegin(),(c).rend()
#define tr(i,c)  for(auto i=(c).begin(); i!=(c).end(); ++i)
#define found(s,e)  ((s).find(e)!=(s).end())
#define mset(arr,val)  memset(arr,val,sizeof(arr))
#define mid(x,y) ((x)+((y)-(x))/2)
#define IN(x,a,b) ((a)<=(x)&&(x)<=(b))
#define cons make_pair

template<class T> inline void amin(T & a, T const & b) { a = min(a, b); }
template<class T> inline void amax(T & a, T const & b) { a = max(a, b); }
template<typename X, typename T> auto vectors(X x, T a) { return vector<T>(x, a); }
template<typename X, typename Y, typename Z, typename... Zs> auto vectors(X x, Y y, Z z, Zs... zs) { auto cont = vectors(y, z, zs...); return vector<decltype(cont)>(x, cont); }


ll gcd(ll a, ll b) { while(a) swap(a, b%=a); return b; }

const ll MOD=1000000007LL;

ll ADD(ll x, ll y) { return (x+y) % MOD; }
ll SUB(ll x, ll y) { return (x-y+MOD) % MOD; }
ll MUL(ll x, ll y) { return x*y % MOD; }
ll POW(ll x, ll e) { ll v=1; for(; e; x=MUL(x,x), e>>=1) if (e&1) v = MUL(v,x); return v; }
ll DIV(ll x, ll y) { /*assert(y%MOD!=0);*/ return MUL(x, POW(y, MOD-2)); }
// ll comb(ll n, ll k) { ll v=1; for(ll i=1; i<=k; i++) v = DIV(MUL(v, n-i+1),i); return v; }
//



vvi nxt;
vi visited;

llll sub(int u){
    visited[u] = true;
    vector<llll> tmp;
    for (int v: nxt[u]) {
        if (visited[v]) continue;
        tmp.pb( sub(v) );
    }
    // cerr << u << tmp << endl;
    int L = tmp.size();
    if (L==0) return llll(1,1);
    ll bl=1, wh=1;
    rep(i,L){
        bl = MUL(bl, tmp[i].second);
        wh = MUL(wh, ADD(tmp[i].first, tmp[i].second));
    }
    // debug("sub(%d) = %lld %lld\n", u, bl, wh);
    return llll(bl,wh);
}

ll solve(int N, vi& x, vi& y) {
    nxt.resize(N);
    rep(i,N-1) {
        nxt[x[i]].pb(y[i]);
        nxt[y[i]].pb(x[i]);
    }
    // dp.assign(N, -1);
    visited.assign(N, 0);

    llll z = sub(0);
    return ADD(z.first, z.second);
}

int main() {
    int N; scanf("%d",&N);
    vi x(N-1), y(N-1);
    rep(i,N-1) {
        scanf("%d%d", &x[i], &y[i]);
        x[i]--; y[i]--;
    }
    cout << solve(N,x,y) << endl;
    return 0;
}

Submission Info

Submission Time
Task P - Independent Set
User naoya_t
Language C++14 (GCC 5.4.1)
Score 100
Code Size 3461 Byte
Status
Exec Time 48 ms
Memory 13824 KB

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:109:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     int N; scanf("%d",&N);
                          ^
./Main.cpp:112:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &x[i], &y[i]);
                                    ^

Test Cases

Set Name Score / Max Score Test Cases
All 100 / 100 0_00, 0_01, 0_02, 0_03, 1_00, 1_01, 1_02, 1_03, 1_04, 1_05, 1_06, 1_07, 1_08, 1_09, 1_10, 1_11, 1_12, 1_13, 1_14, 1_15
Case Name Status Exec Time Memory
0_00 1 ms 256 KB
0_01 1 ms 256 KB
0_02 1 ms 256 KB
0_03 1 ms 256 KB
1_00 1 ms 256 KB
1_01 48 ms 13824 KB
1_02 31 ms 9460 KB
1_03 29 ms 9716 KB
1_04 34 ms 8148 KB
1_05 30 ms 7572 KB
1_06 37 ms 7552 KB
1_07 39 ms 7168 KB
1_08 42 ms 7040 KB
1_09 44 ms 6912 KB
1_10 44 ms 6784 KB
1_11 44 ms 6784 KB
1_12 43 ms 6784 KB
1_13 45 ms 7296 KB
1_14 45 ms 8960 KB
1_15 46 ms 11264 KB