結構體存儲

 1 struct Edge
 2 {  
 3    int to,val,next;
 4 }edge[maxn];
 5 int head[maxn];
 6 void addedge(int x,int y,int val)
 7 {
 8   edge[++cnt].to=y;
 9   edge[cnt].val=val;
10   edge[cnt].next=head[x];
11   head[x]=cnt;
12 }

調用

1 void use(int x){
2     int u=x;//x為頭結點;
3     for
 
(int i=head[u];i!=-1;i=E[i].next){
4         v=E[i].to;
5          
6     }
7 }

vector存儲

 1 #include <cstdio>
 2 #include <vector>
 3 struct edge{
 4     int v,w;
 5     edge(int _v,int _w){
 6         v=_v;w=_w;
 7     }
 8 };
 9 vector <edge> g[maxn];
10 void
 
 add(int x,int y,int z){
11     g[x].push_back(edge(y,z));
12 }

調用

1 void use(int x){
2     int ans=g[x].size();
3     for(int i=0;i<ans;i++){
4         int v=g[x][i].v;
5          
6     }
7 }

數組模擬

 1 const int maxn = 1e5+10;
 2 const int maxr = 2e5+10;
 3 int index = 1
 
, to[maxn], w[maxn], pre[maxn], p1[maxn];
 4     //插入
 5     int x, y, z;
 6     for(int i = 0; i < n; ++i){
 7         scanf("%d%d%d", &x, &y, &z);
 8         to[index] = y, w[index] = z, pre[index] = p[x], p[x] = index++;
 9     }
10     
11     //遍歷
12     for(int i = p[v]; i; i = pre[i]){
13         int vv = to1[i], ww = w[i];
14     }

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例題：一般與搜索一起用

南洋理工 --吝嗇的國度 http://acm.nyist.net/JudgeOnline/problem.php?pid=20

vector（動態數組） 好用

上代碼

 1 #include <iostream>
 2 #include <string.h>
 3 #include <vector>
 4 #include <algorithm>
 5 using namespace std;
 6 const int maxn = 1e5+10;
 7 vector<int> v[maxn];
 8 int a[maxn];
 9 void dfs(int x){
10     for(int i = 0; i < v[x].size(); i++){
11         if(!a[v[x][i]]) a[v[x][i]] = x, dfs(v[x][i]); 
12     }
13 }
14 int main(){
15      // freopen("in.txt", "r", stdin);
16      // freopen("out.txt", "w", stdout);
17     int t,n,m,p,q;
18     cin>>t;
19     while(t--){
20         cin>>n>>m;
21         for(int i = 0; i < n-1; i++){
22             cin>>p>>q;
23             v[p].push_back(q);
24             v[q].push_back(p);
25         }
26         dfs(m);
27         a[m]=-1;
28         for(int i = 1; i <= n; i++){
29             if(i != 1) cout<<" ";
30             cout<<a[i];
31         }
32         cout<<endl;
33         memset(v,0,sizeof(v));
34         memset(a,0,sizeof(a));
35     }
36     return 0;
37 }

hdu 2586 ：http://acm.split.hdu.edu.cn/showproblem.php?pid=2586

 1 #include <iostream>
 2 #include <string.h>
 3 #include <vector>
 4 #include <algorithm>
 5 using namespace std;
 6 const int maxn = 1e5+10;
 7 vector<int> v[maxn];
 8 vector<int> vn[maxn];
 9 int a[maxn];
10 int dfs(int x, int y, int sum){
11     for(int i = 0; i < v[x].size(); i++){
12          // cout<<sum<<endl;
13         if(v[x][i] == y)  {cout<<sum+vn[x][i]<<endl; return 0;}
14         else if(!a[v[x][i]])
15         a[v[x][i]] = 1, dfs(v[x][i], y, sum+vn[x][i]);
16     }
17 }
18 int main(){
19        // freopen("in.txt", "r", stdin);
20        // freopen("out.txt", "w", stdout);
21     int n, flag = 0;
22     cin>>n;
23     while(n--){
24         if(flag) cout<<endl;
25         memset(v, 0, sizeof(v));
26         memset(vn, 0, sizeof(vn));
27         int x, y, p, q, r;
28         cin>>x>>y;
29         for(int i = 0; i < x-1; i++){
30             cin>>p>>q>>r;
31             v[p].push_back(q);
32             vn[p].push_back(r);
33             v[q].push_back(p);
34             vn[q].push_back(r);
35         }
36         for(int i = 0; i < y; i++){
37             memset(a, 0, sizeof(a));
38             cin>>p>>q;
39             a[p] = 1;
40             dfs(p, q, 0);
41         }
42         flag = 1;
43     }
44     return 0;
45 }

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