Starry

发表于 更新于 分类于 本文字数： 337 阅读时长 ≈ 1 分钟

考虑 -> ，发现符合条件当且仅当形成的基环树环长为，注意要特判

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
#include <bits/stdc++.h>
/*
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
*/
using namespace std;

const double eps = 1e-10;
const double pi = 3.1415926535897932384626433832795;
const double eln = 2.718281828459045235360287471352;

#define f(i, a, b) for (int i = a; i <= b; i++)
#define scan(x) scanf("%d", &x)
#define mp make_pair
#define pb push_back
#define lowbit(x) (x&(-x))

#define fi first
#define se second
#define SZ(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define summ(a) (accumulate(all(a), 0ll))

typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;

using ll=long long;

struct dsu{
    vector<int> fa,sz;
    dsu(int n){
        fa.resize(n+1),sz.resize(n+1);
        for(int i=1;i<=n;++i)fa[i]=i,sz[i]=1;
    }
    int fnd(int x){
        return fa[x]==x?x:fa[x]=fnd(fa[x]);
    }
    bool merge(int x ,int y){
        int oa=fnd(x),ob=fnd(y);
        if(oa!=ob){
            fa[ob]=oa,sz[oa]+=sz[ob];
            return true;
        }
        return false;
    }
};

int tt,n,k,b[(int)1e5+9];
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>tt;
    while(tt--){
    	cin>>n>>k;
    	dsu d(n);
    	vector<vector<int>> g(n+1,vector<int>());
    	vector<int> dis(n+1,0);
    	bool same=true;
    	for(int i=1;i<=n;++i){
    		cin>>b[i];
    		d.merge(i,b[i]),g[i].push_back(b[i]);
    		same&=b[i]==i;
    	}

    	auto dfs=[&](auto self,int u,int fa,int dep)->ll{
    		dis[u]=dep;
    		ll res=0ll;
    		for(auto it:g[u]){
    			if(dis[it])res=max(res,dep-dis[it]+1ll);
    			else res=max(res,self(self,it,u,dep+1));
    		}
    		//cerr<<res<<"::\n";
    		return res;
    	};

    	bool ok=true;
    	if(k==1&&!same)ok=false;
    	f(i,1,n)if(d.fnd(i)==i)ok&=dfs(dfs,i,0,1)==k;
    	cout<<(ok?"YES\n":"NO\n");

    }
    return 0;
}

发表于 更新于 分类于 本文字数： 350 阅读时长 ≈ 1 分钟

果然要自己写一遍！！！

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
#include <bits/stdc++.h>
/*
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
*/
using namespace std;

const double eps = 1e-10;
const double pi = 3.1415926535897932384626433832795;
const double eln = 2.718281828459045235360287471352;

#define f(i, a, b) for (int i = a; i <= b; i++)
#define scan(x) scanf("%d", &x)
#define mp make_pair
#define pb push_back
#define lowbit(x) (x&(-x))

#define fi first
#define se second
#define SZ(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define summ(a) (accumulate(all(a), 0ll))

typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;

using ll=long long;

//HDU 7339
const ll qz[]={998244353,1000000007,-998244353-1000000007};
ll n,a[(int)1e5+9],sz[(int)1e5+9],son[(int)1e5+9],dfn[(int)1e5+9],revdfn[(int)1e5+9],dfncnt,ans;
ll val[(int)1e5+9];
vector<int> g[(int)1e5+9];

void dfs(int u,int fa){
	val[u]=val[fa]+a[u];
	sz[u]=1,dfn[u]=++dfncnt,revdfn[dfncnt]=u;
	for(auto it:g[u])if(it!=fa){
		dfs(it,u);
		son[u]=sz[it]>sz[son[u]]?it:son[u],sz[u]+=sz[it];
	}
}

map<ll,int> cn;

void dsu(int u,int fa){
	for(auto it:g[u])if(it!=fa&&it!=son[u]){
		dsu(it,u);
		cn.clear();
	}
	if(son[u])dsu(son[u],u);

	auto cal=[&](int now,int lca,int lcafa){
		ll need=val[now]-val[lca]-val[lcafa];
		return cn[-need];
	};

	for(auto it:g[u])if(it!=fa&&it!=son[u]){
		for(int i=dfn[it];i<dfn[it]+sz[it];++i){
			ans+=cal(revdfn[i],u,fa);
		}
		for(int i=dfn[it];i<dfn[it]+sz[it];++i)cn[val[revdfn[i]]]+=1;
	}
	ans+=cal(u,u,fa);
	cn[val[u]]+=1;
}

int main()
{
    scanf("%lld",&n);
    for(int i=1;i<=n;++i){
    	char c;
    	scanf(" %c",&c);
    	a[i]=qz[c-'a'];
    }
    for(int i=1,x,y;i<n;++i){
    	scanf("%d%d",&x,&y);
    	g[x].push_back(y),g[y].push_back(x);
    }
    dfs(1,0);
    dsu(1,0);
    printf("%lld\n", ans);
    return 0;
}

发表于 更新于 分类于 本文字数： 346 阅读时长 ≈ 1 分钟

脑子一直在降智

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
#include <bits/stdc++.h>
/*
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
*/
using namespace std;

const double eps = 1e-10;
const double pi = 3.1415926535897932384626433832795;
const double eln = 2.718281828459045235360287471352;

#define f(i, a, b) for (int i = a; i <= b; i++)
#define scan(x) scanf("%d", &x)
#define mp make_pair
#define pb push_back
#define lowbit(x) (x&(-x))

#define fi first
#define se second
#define SZ(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define summ(a) (accumulate(all(a), 0ll))

typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;

using ll=long long;
const int mod=1e9+7;

ll powmod(ll a,ll b){
    a%=mod;
    int res=1;
    for(;b>0;b>>=1,a=1ll*a*a%mod)if(b&1)res=1ll*res*a%mod;
    return res;
}

ll tt,n,q,xs[40][(int)1e5+9],nxt[40][(int)1e5+9],yx[40][(int)1e5+9],to[(int)1e5+9],k[(int)1e5+9],b[(int)1e5+9];

void solve(){
    cin>>n>>q;
    f(i,1,n)cin>>k[i];
    f(i,1,n)cin>>b[i];
    f(i,1,n)cin>>to[i];
    f(i,1,n){
        xs[0][i]=k[to[i]],yx[0][i]=b[to[i]],nxt[0][i]=to[i];
    }
    for(int i=1;i<=34;++i){
        for(int j=1;j<=n;++j){
            xs[i][j]=xs[i-1][nxt[i-1][j]]*xs[i-1][j]%mod;
            yx[i][j]=(yx[i-1][j]*xs[i-1][nxt[i-1][j]]%mod+yx[i-1][nxt[i-1][j]])%mod;
            nxt[i][j]=nxt[i-1][nxt[i-1][j]];
        }
    }

    for(int i=1,x,y,z;i<=q;++i){
        cin>>x>>y>>z;
        ll ans=z;
        while(y>0){
            int tp=log2(y);
            ans=(xs[tp][x]*ans%mod+yx[tp][x])%mod;
            x=nxt[tp][x],y-=1ll<<tp;
        }
        cout<<ans<<"\n";
    }
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>tt;
    while(tt--)solve();
    return 0;
}

发表于 更新于 本文字数： 363 阅读时长 ≈ 1 分钟

警钟长鸣！提交

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
#include <bits/stdc++.h>
/*
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
*/
using namespace std;

const double eps = 1e-10;
const double pi = 3.1415926535897932384626433832795;
const double eln = 2.718281828459045235360287471352;

#define f(i, a, b) for (int i = a; i <= b; i++)
#define scan(x) scanf("%d", &x)
#define mp make_pair
#define pb push_back
#define lowbit(x) (x&(-x))

#define fi first
#define se second
#define SZ(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define summ(a) (accumulate(all(a), 0ll))

typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;

using ll=long long;

ll n,m,k,d,s[(int)3e5+9],now[(int)3e5+9],dep[(int)3e5+9],dis[(int)3e5+9],cost[(int)3e5+9],qsb[(int)3e5+9],ans=1e18;
vector<int> g[(int)1e5+9]; 
bitset<(int)3e5+9> vis;


int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>n>>m>>k>>d;
    for(int i=1,x,y;i<=m;++i){
    	cin>>x>>y;
    	g[x].push_back(y),g[y].push_back(x);
    }
    for(int i=1;i<=m;++i){
    	s[i]=s[i-1]+d-(i-1)%d;
    }
    for(int i=1;i<=d;++i){
    	now[i]=now[i-1]+i;
    }
    {
    	queue<int> q;
    	q.push(n);
    	dis[n]=1;
    	while(!q.empty()){
    		auto p=q.front();q.pop();
    		for(auto it:g[p])if(!dis[it])dis[it]=dis[p]+1,q.push(it);
    	}
    }
    {
    	queue<int> q;
    	q.push(k);
    	dep[k]=d;
    	while(!q.empty()){
    		auto p=q.front();q.pop();
    		for(auto it: g[p]){
    			if(!dep[it]){
    				dep[it]=dep[p]-1;
    				if(dep[it])q.push(it);
    			}
    		}
    	}
    }
    {
    	priority_queue<pair<ll,int>,vector<pair<ll,int>>,greater<pair<ll,int>>>q;
    	q.push({0,1});
    	memset(cost,0x3f,sizeof(cost));
    	cost[1]=0ll;
    	while(!q.empty()){
    		auto [aa,bb]=q.top();q.pop();
    		if(vis[bb])continue;
    		vis[bb]=1;
    		for(auto it:g[bb]){
    			if(dep[it]){
    				if(cost[it]>cost[bb]+dep[it]){
    					cost[it]=cost[bb]+dep[it];
    					q.push({cost[it],it});
    				}
    			}else if(!vis[it]) ans=min(ans,cost[bb]+s[dis[it]]);
    			//cerr<<ans<<"::"<<bb<<"-->"<<it<<"????"<<dep[it]<<"\n";
    		}
    	}
    }
    ans=min(ans,cost[n]);

    cout<<ans;
    return 0;
}
0%