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Submission #634621

# Submission time Handle Problem Language Result Execution time Memory
634621 2022-08-24T15:57:11 Z MohammadAghil Subtree (INOI20_subtree) C++17
12 / 100
 144 ms 36320 KB 
#include <bits/stdc++.h>
//#pragma GCC optimize("Ofast,unroll-loops")
//#pragma GCC target ("avx2")
using namespace std;

typedef long long ll;
typedef pair<int, int> pp;

#define rep(i,l,r) for(int i = (l); i < (r); i++)
#define per(i,r,l) for(int i = (r); i >= (l); i--)
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define pb push_back
#define ff first
#define ss second

void dbg(){
    cerr << endl;
}
template<typename Head, typename... Tail> void dbg(Head h, Tail... t){
    cerr << " " << h << ",";
    dbg(t...);
}
#define er(...) cerr << __LINE__ << " <" << #__VA_ARGS__ << ">:", dbg(__VA_ARGS__)

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

void IOS(){
    cin.tie(0) -> sync_with_stdio(0);
//    #ifndef ONLINE_JUDGE
//        freopen("inp.txt", "r", stdin);
//        freopen("out.txt", "w", stdout);
//    #endif
}

const ll mod = 1e9 + 7, maxn = 1e5 + 5, lg = 19, inf = ll(1e9) + 5;

vector<int> adj[maxn], lis[maxn];
vector<pp>  adj2[maxn];
bool vis[maxn], king[maxn];
int cnt_cycle, grp[maxn];

pp dfs(int r, int p){
    pp res = {-1, -1};
    vis[r] = true;
    for(int c: adj[r]) if(c - p){
        if(vis[c]){
            if(res.ff + 1) continue;
            res = {c, cnt_cycle++};
            grp[r] = res.ss;
        }else{
            pp ret = dfs(c, r);
            if(ret.ff + 1){
                assert(res.ff == -1);
                grp[r] = ret.ss;
                res = ret;
            }
        }
    }
    if(res.ff == r) res = {-1, -1};
    return res;
}

ll slv(vector<ll> a){
    if(sz(a) < 3) return a[0];
    int n = sz(a);
    vector<ll> suf(n + 1);
    suf[n] = 1;
    per(i,n-1,0){
        suf[i] = suf[i+1]*a[i]%mod;
    }
    ll cr = 0, mul = a[0];
    rep(i,2,n+1) cr += suf[i], cr %= mod;
    ll res = 0;
    rep(i,0,n-1){
        res = (res + cr*mul)%mod;
        cr = (cr - suf[i + 2] + mod)%mod;
        mul = mul*a[i + 1]%mod;
    }
    return res;
}

ll slv2(vector<ll> a){
    ll res = 0;
    ll cr = 0;
    rep(i,0,sz(a)){
        cr = (cr + 1)*a[i]%mod;
        res = (res + cr)%mod;
    }
    return res;
}

ll dp[maxn], dp2[maxn], ans;
void dfs2(int r, int p){
    for(auto[c, u]: adj2[r]){
        if(c - p){
            king[u] = true;
            dfs2(c, r);
        }
    }
    int pos = 0, ptr = 0;
    for(int u: lis[r]){
        dp2[u] = 1;
        for(int c: adj[u]) if(grp[u] - grp[c] && grp[c] - p){
            dp2[u] = dp2[u]*(dp[c] + 1)%mod;
        }
        if(king[u]) pos = ptr;
        ptr++;
    }
    vector<ll> tmp, tmp2;
    rep(i,pos,sz(lis[r])) tmp.pb(dp2[lis[r][i]]);
    rep(i,0,pos) tmp.pb(dp2[lis[r][i]]);
    rep(i,pos+1,sz(lis[r])) dp[lis[r][i]] = dp2[lis[r][i]], tmp2.pb(dp[lis[r][i]]);
    rep(i,0,pos) dp[lis[r][i]] = dp2[lis[r][i]], tmp2.pb(dp[lis[r][i]]);
    dp[lis[r][pos]] = slv(tmp);
    ans = (ans + dp[lis[r][pos]] + slv2(tmp2))%mod;
}

void chk(int r, int p){
    vis[r] = false;
    for(auto[c, y]: adj2[r]) if(c - p){
        assert(vis[c]);
        chk(c, r);
    }
}

int main(){ IOS();
    int n, m; cin >> n >> m;
    rep(i,0,m){
        int u, v; cin >> u >> v; u--, v--;
        adj[u].pb(v), adj[v].pb(u);
    }
    fill(grp, grp + n, -1);
    dfs(0, -1);
    rep(i,0,n){
        if(grp[i] == -1) grp[i] = cnt_cycle++;
        lis[grp[i]].pb(i);
    }
    rep(i,0,n){
        for(int c: adj[i]){
            if(grp[i] - grp[c]){
                adj2[grp[i]].pb({grp[c], c});
            }
        }
    }
    king[0] = true;
    dfs2(grp[0], -1);
    chk(0, -1);
//    rep(i,0,n){
//        er(i+1, dp[i], dp2[i], king[i], grp[i]);
//    }
//    er(slv2({1, 2, 3, 4}));
    cout << ans << '\n';
    return 0;
}

Subtask #1
0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 7380 KB Output is correct
2 Correct 4 ms 7380 KB Output is correct
3 Correct 5 ms 7380 KB Output is correct
4 Correct 4 ms 7380 KB Output is correct
5 Correct 4 ms 7380 KB Output is correct
6 Correct 4 ms 7380 KB Output is correct
7 Correct 3 ms 7380 KB Output is correct
8 Correct 4 ms 7380 KB Output is correct
9 Incorrect 4 ms 7380 KB Output isn't correct
10 Halted 0 ms 0 KB -

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 7380 KB Output is correct
2 Correct 10 ms 8612 KB Output is correct
3 Correct 110 ms 19528 KB Output is correct
4 Correct 114 ms 19624 KB Output is correct
5 Correct 115 ms 19540 KB Output is correct
6 Correct 126 ms 19532 KB Output is correct
7 Correct 137 ms 32612 KB Output is correct
8 Correct 131 ms 27856 KB Output is correct
9 Correct 130 ms 28152 KB Output is correct
10 Correct 99 ms 20652 KB Output is correct
11 Correct 94 ms 19656 KB Output is correct
12 Correct 127 ms 19020 KB Output is correct
13 Correct 123 ms 18912 KB Output is correct
14 Correct 96 ms 25284 KB Output is correct
15 Correct 144 ms 34636 KB Output is correct
16 Correct 132 ms 36320 KB Output is correct
17 Correct 126 ms 19032 KB Output is correct
18 Correct 128 ms 18992 KB Output is correct
19 Correct 133 ms 19072 KB Output is correct
20 Correct 84 ms 20000 KB Output is correct
21 Correct 93 ms 20240 KB Output is correct
22 Correct 90 ms 20144 KB Output is correct

Subtask #3
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 7380 KB Output is correct
2 Correct 4 ms 7380 KB Output is correct
3 Correct 5 ms 7380 KB Output is correct
4 Correct 4 ms 7380 KB Output is correct
5 Correct 4 ms 7380 KB Output is correct
6 Correct 4 ms 7380 KB Output is correct
7 Correct 3 ms 7380 KB Output is correct
8 Correct 4 ms 7380 KB Output is correct
9 Incorrect 4 ms 7380 KB Output isn't correct
10 Halted 0 ms 0 KB -

Subtask #4
0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 7380 KB Output is correct
2 Correct 4 ms 7380 KB Output is correct
3 Correct 5 ms 7380 KB Output is correct
4 Correct 4 ms 7380 KB Output is correct
5 Correct 4 ms 7380 KB Output is correct
6 Correct 4 ms 7380 KB Output is correct
7 Correct 3 ms 7380 KB Output is correct
8 Correct 4 ms 7380 KB Output is correct
9 Incorrect 4 ms 7380 KB Output isn't correct
10 Halted 0 ms 0 KB -