Starry

发表于 更新于 分类于 本文字数： 305 阅读时长 ≈ 1 分钟

随机化冲过去

感谢unrated *2

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#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{
    vi fa,sz;
    dsu(int n){
        fa.resize(n+1),sz.resize(n+1);
        for(int i=0;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,m,sbctr;

bitset<(int)2e5+9> vis;
vector<pii> v;
bool solve(){
    vis.reset();
    for(int i=0;i<m;++i){
        vis[i]=rand()&1;
    }
    dsu d1(n),d2(n);
    for(int i=0;i<m;++i){
        if(vis[i]){
            if(!d1.merge(v[i].first,v[i].second))
                return true;
        }else{
            if(!d2.merge(v[i].first,v[i].second))
                return true;
        }
    }
    return false;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    srand(time(0));
    cin>>tt;
    f(sb,1,tt){
        vis.reset();
        cin>>n>>m;
        v.resize(m);
        for(int i=1,x,y;i<=m;++i){
            cin>>v[i-1].first>>v[i-1].second;
        }
        while(solve());
        f(i,0,m-1)cout<<vis[i];
        cout<<"\n";
    }
    return 0;
}

发表于 更新于 分类于 本文字数： 245 阅读时长 ≈ 1 分钟

维护步数，两张纸条到达的行数

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#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 a[100][100],n,m,dp[(int)200][100][100]; 
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>n>>m;
    f(i,1,n)f(j,1,m)cin>>a[i][j];
    for(int i=1;i<=n+m-1;++i){
    	for(int j=1;j<=n;++j){
    		for(int k=1;k<=n;++k){
    			if(i-j<0||i-k<0||i-j+1>m||i-k+1>m)continue;
    			dp[i][j][k]=max({dp[i-1][j][k],dp[i-1][j-1][k],dp[i-1][j][k-1],dp[i-1][j-1][k-1]})+(j==k?a[j][i-j+1]:a[j][i-j+1]+a[k][i-k+1]);
    		}
    	}
    }
    cout<<dp[n+m-1][n][n];
    return 0;
}

发表于 更新于 分类于 本文字数： 491 阅读时长 ≈ 2 分钟

菜狗不会dp 网络流复健

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#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;

int n,m,a[100][100],tot=1,hd[(int)7e3+9],cur[(int)7e3+9],dep[(int)7e3+9],res;
bitset<(int)7e3+9> vis;
struct Edge{
	int to,nxt,v,c;
}e[(int)1e5+9];
void add(int u,int v,int w,int c){
	e[++tot]={v,hd[u],w,c},hd[u]=tot;
	e[++tot]={u,hd[v],0,-c},hd[v]=tot;
}

bool bfs(int st,int en){
	memset(dep,0,sizeof(dep));
	memcpy(cur,hd,sizeof(hd));
	queue<int>q;
	q.push(st);
	dep[st]=1,vis[st]=1;
	while(!q.empty()){
		auto u=q.front();
		q.pop(),vis[u]=0;
		for(int eg=hd[u];eg;eg=e[eg].nxt){
			if(dep[e[eg].to]<dep[u]+e[eg].c&&e[eg].v){
				dep[e[eg].to]=dep[u]+e[eg].c;
				if(!vis[e[eg].to])q.push(e[eg].to),vis[e[eg].to]=1;
			}
		}
	}
	return dep[en]!=0;
}

int dfs(int u,int en,int flow){
	if(u==en)return flow;
	vis[u]=1;
	int r=flow;
	for(int eg=cur[u];eg&&r;eg=e[eg].nxt){
		cur[u]=eg;
		if(e[eg].v&&dep[e[eg].to]==dep[u]+e[eg].c&&!vis[e[eg].to]){
			int c=dfs(e[eg].to,en,min(r,e[eg].v));
			if(c)res+=c*e[eg].c;
			r-=c;
			e[eg].v-=c,e[eg^1].v+=c;
		}
	}
	vis[u]=0;
	return flow-r;
}

int dinic(int st,int en){
	int ret=0;
	while(bfs(st,en)){
		ret+=dfs(st,en,0x3f3f3f3f);
	}
	return ret;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>n>>m;
    f(i,1,n)f(j,1,m)cin>>a[i][j];
    for(int i=1;i<=n;++i){
    	for(int j=1;j<=m;++j){
    		if(i!=n)add(i*m+j-m+n*m,i*m+j,1,a[i+1][j]);
    		if(j!=m)add(i*m-m+j+n*m,i*m-m+j+1,1,a[i][j+1]);
    		if((i==1&&j==1)||(i==n&&j==m)){
    			add(i*m-m+j,i*m-m+j+n*m,2,0);
    		}else add(i*m-m+j,i*m-m+j+n*m,1,0);
    	}
    }
    dinic(1,2*n*m);
    cout<<res;
    return 0;
}

发表于 更新于 本文字数： 29 阅读时长 ≈ 1 分钟

链式不相邻问题：

环形不相邻问题：

发表于 更新于 分类于 本文字数： 377 阅读时长 ≈ 1 分钟 
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#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=998244353,g=3,gi=332748118,NR=1<<21;

int A[NR],rev[NR],bit,lim,n,k,len,res;

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

void NTT(int *a,int type){
	for(int i=0;i<lim;++i)if(i<rev[i])swap(a[i],a[rev[i]]);
	for(int k=1;k<lim;k<<=1){
		int wn=powmod(type==1?g:gi,(mod-1)/(k<<1));
		for(int i=0;i<lim;i+=(k<<1)){
			int w=1;
			for(int j=0;j<k;++j,w=1ll*w*wn%mod){
				int x=a[i+j],y=1ll*w*a[i+j+k]%mod;
				a[i+j]=(x+y)%mod,a[i+j+k]=(x-y+mod)%mod;
			}
		}
	}
	if(type==1)return ;
	int invn=powmod(lim,mod-2);
	for(int i=0;i<lim;++i){
		a[i]=1ll*a[i]*invn%mod;
	}
}

void poly_fast(int *a,int b){
	lim=1,bit=0;
	while(lim<=len*2)lim<<=1,bit+=1;
	for(int i=0;i<lim;++i)rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
	NTT(a,1);
	for(int i=0;i<lim;++i)a[i]=powmod(a[i],b);
	NTT(a,0);
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>n>>k;
    len=9*n/2;
    for(int i=1,x;i<=k;++i){
    	cin>>x;
    	A[x]=1;
    }
    poly_fast(A,n/2);
    for(int i=0;i<=lim;++i){
    	res=(res+1ll*A[i]*A[i]%mod)%mod;
    }
    cout<<res;
    return 0;
}
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