【BZOJ】【Usaco刷水合集】

成为权限狗了……蛋疼地刷点Usaco的水题，话说明天又要滚回新校被文化科虐爆了，不爽啊啊啊

/**************************************************************
    Problem: 1600
    User: zky
    Language: C++
    Result: Accepted
    Time:0 ms
    Memory:1280 kb
****************************************************************/
 
#include<iostream>
using namespace std;
int n,f[2505];
int main(){
  cin>>n;
  f[4]=1;
  for (int i=5;i<=n;i++)
    if (!(i&1)) f[i]=f[i-1]+i/2-1;
    else f[i]=f[i-1]+(i-2)*(i/2-1);
  cout<<f[n]<<endl;
  return 0;
}

/**************************************************************
    Problem: 1601
    User: zky
    Language: C++
    Result: Accepted
    Time:92 ms
    Memory:2780 kb
****************************************************************/
 
//ID:zky
#include<cstdio>
#include<vector>
#include<iostream>
#include<algorithm>
using namespace std;
const int maxn=310;
int n;
struct edge{
    int u,v,w,ind;
    bool operator < (const edge &e)const{
        return w<e.w;
    }
};int tot;
edge edges[maxn*maxn+maxn];
int fa[maxn],minn=100000;
int find(int x){
    if(x!=fa[x])return fa[x]=find(fa[x]);return x;
}
int main(){
    int n;scanf("%d",&n);fa[n+1]=n+1;
    for(int i=1;i<=n;i++){
        fa[i]=i;
        int w;scanf("%d",&w);minn=min(minn,w);
        edges[tot]=(edge){i,n+1,w,tot};tot++;
    }
    for(int i=1;i<=n;i++)
    for(int j=1;j<=n;j++){
        int x;scanf("%d",&x);
        if(i>=j)continue;        
        edges[tot]=(edge){i,j,x,tot};tot++;
    }sort(edges,edges+tot);
    int ans=0,get=0;
    for(int i=0;i<tot;i++){
        int u=edges[i].u,v=edges[i].v;
        if(find(u)!=find(v)){
            fa[find(u)]=find(v);
            if(edges[i].ind<=n)get=1;
            ans+=edges[i].w;
        }
    }if(!get)ans+=minn;
    cout<<ans<<endl;
    return 0;
}

/**************************************************************
    Problem: 1602
    User: zky
    Language: C++
    Result: Accepted
    Time:152 ms
    Memory:1288 kb
****************************************************************/
 
#include<bits/stdc++.h>
using namespace std;typedef pair<int,int> pii;
vector<pair<int,int> >G[1001];
int n,m;
main(){
    cin>>n>>m;int s,t;
    for(int i=0;i<n-1;i++){
        int u,v,w;cin>>u>>v>>w;
        G[u].push_back(pii(v,w));
        G[v].push_back(pii(u,w));
    }while(m--){int d[1233];int vis[1233];memset(d,0x7f,sizeof(d));
    memset(vis,0,sizeof(vis));cin>>s>>t;
        queue<int>q;q.push(s);d[s]=0;while(!q.empty()){
            int u=q.front();q.pop();vis[u]=0;
            for(int i=0;i<G[u].size();i++){
                int v=G[u][i].first,w=G[u][i].second;
                if(d[v]>d[u]+w){
                    d[v]=d[u]+w;if(!vis[v]){
                        vis[v]=1;q.push(v);
                    }
                }
            }
        }cout<<d[t]<<endl;
    }
}

/**************************************************************
    Problem: 1603
    User: zky
    Language: C++
    Result: Accepted
    Time:20 ms
    Memory:1280 kb
****************************************************************/
 
#include<bits/stdc++.h>
using namespace std;
int n;
int next[1001];
int w[1001];
int main(){
    cin>>n;
    for(int i=0;i<n-1;i++){
        int u,v,ww;cin>>u>>v>>ww;
        next[u]=v;w[u]=ww;
    }int ans=0;
    for(int i=1;i;i=next[i])
        ans^=w[i];
    cout<<ans<<endl;
    return 0;
}

/**************************************************************
    Problem: 1604
    User: zky
    Language: C++
    Result: Accepted
    Time:988 ms
    Memory:4680 kb
****************************************************************/
 
#include<bits/stdc++.h>
using namespace std;
const int maxn=1e5+10;
int n,m,a[maxn],c[maxn];
struct point {
    int x,y,i;
    bool operator<(const point &p)const {
        if(y==p.y)return x<p.x;
        return y<p.y;
    }
} p[maxn];
set<point>mset;
set<point>::iterator ii,it;
bool cmp(point p1,point p2) {
    return p1.x<p2.x;
}
inline int find(int x) {
    int r=x,p;
    while(r!=a[r])r=a[r];
    while(r!=x) {
        p=a[x];
        a[x]=r;
        x=p;
    }
    return r;
}
void unit(int x,int y) {
    x=find(x);
    y=find(y);
    if(x!=y)a[y]=x;
}
void slove() {
    int i,j=1,k,x,y,sum,ans;
    mset.clear();
    mset.insert(p[1]);
    for(i=2; i<=n; i++) {
        while(p[i].x-p[j].x>m&&j<i) {
            mset.erase(p[j]);
            j++;
        }
        mset.insert(p[i]);
        ii=it=mset.find(p[i]);
        ii--;
        it++;
        if(ii!=mset.end()&&abs(ii->y-p[i].y)<=m)unit(i,ii->i);
        if(it!=mset.end()&&abs(it->y-p[i].y)<=m)unit(i,it->i);
    }
    sum=ans=0;
    for(i=1; i<=n; i++)c[find(i)]++;
    for(i=1; i<=n; i++) {
        ans=max(ans,c[i]);
        if(a[i]==i)sum++;
    }
    printf("%d %d\n",sum,ans);
}
int main() {
    int i,j,k,x,y;
    while(scanf("%d%d",&n,&m)!=EOF) {
        for(i=1; i<=n; i++) {
            scanf("%d%d",&x,&y);
            p[i].x=x+y;
            p[i].y=x-y;
            a[i]=i;
            c[i]=0;
        }
        sort(p+1,p+n+1,cmp);
        for(i=1; i<=n; i++)p[i].i=i;
        slove();
    }
    return 0;
}

/**************************************************************
    Problem: 1606
    User: zky
    Language: C++
    Result: Accepted
    Time:280 ms
    Memory:1340 kb
****************************************************************/
 
#include <bits/stdc++.h> 
using namespace std;
int c,h,v[5001]; 
bool f[50001];
int main() { 
    cin>>c>>h;
    for(int i=1;i<=h;i++) cin>>v[i]; 
    f[0] = true; 
    for(int i=1;i<=h;i++) 
    for(int j=c;j>=v[i];j--){ 
        if (!f[j]&&f[j-v[i]]) 
        f[j]=true; 
    } 
    int ans=c; 
    while(ans>1&&!f[ans]) 
        ans--; cout<<ans<<endl;
    return 0; 
}