poj刷题记录

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<algorithm>
 5 #define ll long long
 6 using namespace std;
 7 int gcd(int a,int b)
 8 {
 9     return b?gcd(b,a%b):a;
10 }
11 bool vis[1000000];
12 int main()
13 {
14     int n;
15     while(cin>>n)
16     {
17         memset(vis,0,sizeof(vis));
18         int ans1 = 0,ans2 = 0;
19         for(ll i=1;i*i<=2*n;i+=2)
20             for(ll j=i+2;j*j<=2*n;j+=2)
21             {
22                 if(i*i+j*j>2*n)break;
23                 if(gcd(i,j)!=1 ||i==j)continue;
24                 ans1++;
25                 ll a = i*j;
26                 ll b = (j*j-i*i)/2;
27                 ll c = (i*i+j*j)/2;
28                 for(ll k=1;k*c<=n;++k)
29                        vis[k*a]=vis[k*b]=vis[k*c]=1;
30             }
31         for(int i=1;i<=n;++i)
32             if(vis[i])
33                 ans2++;
34         cout<<ans1<<" "<<n-ans2<<endl;
35     }
36     return 0;
37 }

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<algorithm>
 5 #include<vector>
 6 #include<queue>
 7 #include<set>
 8 #include<map>
 9 #include<string>
10 #include<cstdlib>
11 #include<ctime>
12 #define rep(i,a,n) for(int i=(int)(a);i<(int)(n);++i)
13 #define repb(i,a,n) for(int i=(int)(a);i<=(int)(n);++i)
14 #define ll long long
15 #define inf 0x3f3f3f3f
16 using namespace std;
17 struct
18 {
19     int x,y;
20 }arr[20000];
21 map<int,int>mp;
22 int fa[20000],size[20000];
23 int find(int x)
24 {
25     return x==fa[x]?x:fa[x]=find(fa[x]);
26 }
27 void merge(int a,int b)
28 {
29     int fx = find(a),fy = find(b);
30     if(fx==fy)return;
31     fa[fy] = fx;
32     size[fx] += size[fy];
33 }
34 int jh[20000];
35 int main()
36 {
37     int n,m;
38     scanf("%d%d",&n,&m);
39     for(int i=1;i<=n;++i)
40     {
41         scanf("%d%d",&arr[i].x,&arr[i].y);
42         mp[arr[i].x*10001+arr[i].y] = i;
43         size[i]=1;fa[i]=i;
44     }
45     for(int i=1;i<=n;++i)
46     {
47         int mid = arr[i].x*10001+arr[i].y;
48         int dd1 = mp[mid+1],dd2 = mp[mid+10001];
49         if(dd1)
50             merge(dd1,i);
51         if(dd2)
52             merge(dd2,i);
53     }
54     int ans = 0;int cnt =0 ;
55     for(int i=1;i<=n;++i)
56         if(i==fa[i])
57             jh[cnt++] = size[i];
58     sort(jh,jh+cnt);
59     for(int i=0;i<m;++i)
60         ans+=jh[cnt-1-i];
61     printf("%d\n",ans);
62     return 0;
63 }

 1 #include<cstdio>
 2 #include<queue>
 3 #include<iostream>
 4 #include<algorithm>
 5 using namespace std;
 6 const int N = 1e4+10;
 7 int head[N],cnt;
 8 struct Edg
 9 {
10     int v,w,nxt;
11 }e[N*200];
12 void addedge(int u,int v,int w)
13 {
14     e[cnt].v = v;
15     e[cnt].w = w;
16     e[cnt].nxt = head[u];
17     head[u] = cnt++;
18 }
19 int dis[N],vis[N],t[N];
20 queue<int>q;
21 bool spfa(int x,int n)
22 {
23     for(int i=1;i<=n;++i)
24         dis[i] = (1<<30);
25     q.push(x);
26     vis[x]=1;
27     int gs = 0;
28     dis[x]=0;
29     while(!q.empty())
30     {
31         //if(gs>n)return 0;
32         int u = q.front();q.pop();
33         t[u]++;
34         vis[u]=0;
35         if(t[u]>n)return 0;
36         for(int i=head[u];~i;i=e[i].nxt)
37         {
38             int to = e[i].v;
39             if(dis[to]>dis[u]+e[i].w)
40             {
41                 dis[to]=dis[u]+e[i].w;
42                 if(!vis[to])
43                 {
44                     vis[to]=1;
45                     q.push(to);
46                 }
47             }
48         }
49     }
50     return 1;
51 }
52 int main()
53 {
54     ios::sync_with_stdio(false);
55     cin.tie(0);
56     int n,m,q;cin>>n>>m>>q;
57     for(int i=1;i<=n;++i)
58         head[i] = -1;
59     while(m--)
60     {
61         int a,b,w;cin>>a>>b>>w;
62         addedge(a,b,w);
63     }
64     while(q--)
65     {
66         int a,b,w;cin>>a>>b>>w;
67         addedge(b,a,-w);
68     }
69     if(spfa(1,n)==0)
70         cout<<-1<<endl;
71        else if(dis[n]==(1<<30))
72            cout<<-2<<endl;
73     else
74         cout<<dis[n]<<endl;
75     return 0;
76 }