团体程序设计天梯赛-练习集
L2-001 紧急救援 (25 分)
知识点:最短路dij
#include<bits/stdc++.h>
#define debug(x,y) printf("%s = %d\n",x,y);
typedef long long ll;
using namespace std;
inline int read(){int s=0,w=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();//s=(s<<3)+(s<<1)+(ch^48);return s*w;
}
const int INF=0x3f3f3f;
const int maxn=1000;
int a[maxn];
int edge[maxn][maxn];
int n,m,s,d;
int dis[maxn];
int vis[maxn];
int cnt[maxn];
int num_a[maxn];//最短路上的最大救援队
int pathnum[maxn];//最短路的数量
int path[maxn];
void dij(){pathnum[s]=1;dis[s]=0;vis[s]=1;num_a[s]=a[s];for(int i=0;i<n;i++){dis[i]=edge[s][i];if(edge[s][i]<=INF&&i!=s){path[i]=s;num_a[i]=num_a[s]+a[i];pathnum[i]=1;}}for(int i=1;i<n;i++){int now=0;int minn=INF;for(int j=0;j<n;j++){if(vis[j]==0&&dis[j]<minn){now=j;minn=dis[j];}}vis[now]=1;for(int j=0;j<n;j++){if(!vis[j]){if(dis[j]==edge[now][j]+minn){pathnum[j]+=pathnum[now];if(num_a[j]<num_a[now]+a[j]){num_a[j]=num_a[now]+a[j];path[j]=now;}}else if(dis[j]>edge[now][j]+minn){dis[j]=edge[now][j]+minn;num_a[j]=num_a[now]+a[j];pathnum[j]=pathnum[now];path[j]=now;}} }}
}
void print(int now){if(now==s){return ;}print(path[now]);cout<<" "<<now;
}
int main()
{// memset(edge,0x3f3f3f,sizeof(edge));cin>>n>>m>>s>>d;for(int i=0;i<n;i++){dis[i]=INF;for(int j=0;j<n;j++){edge[i][j]=edge[j][i]=INF;}}for(int i=0;i<n;i++)cin>>a[i];for(int i=1;i<=m;i++){int u,v,w;cin>>u>>v>>w;edge[u][v]=w;edge[v][u]=w;}dij();cout<<pathnum[d]<<" "<<num_a[d]<<endl;cout<<s;print(d);
}
L2-002 链表去重 (25 分)
知识点:模拟链表
#include<bits/stdc++.h>
#define debug(x,y) printf("%s = %d\n",x,y);
typedef long long ll;
using namespace std;
inline int read(){int s=0,w=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();//s=(s<<3)+(s<<1)+(ch^48);return s*w;
}
const int maxn=2e5+9;
struct node{int add;int val,next;
}link[maxn],b[maxn];
int vis[maxn];
int tot=0;
int main()
{int beg,n;cin>>beg>>n;for(int i=1;i<=n;i++){int add,val,nex;cin>>add>>val>>nex; link[add].val=val;link[add].next=nex;} int now=beg;
// printf("----\n");while(1){
// printf("now=%d\n",now);if(now==-1){break;}if(vis[abs(link[now].val)]==0){if(now!=beg)printf("%05d\n",now);vis[abs(link[now].val)]=1;printf("%05d %d ",now,link[now].val);
// cout<<now<<" "<<link[now].val<<" "<<link[now].next<<endl;now=link[now].next;} else {b[++tot].next=link[now].next;b[tot].add=now;b[tot].val=link[now].val;now=link[now].next; }} printf("-1\n");if(tot){printf("%05d %d ",b[1].add,b[1].val);for(int i=2;i<=tot;i++){printf("%05d\n%05d %d ",b[i].add,b[i].add,b[i].val);}printf("-1\n");}}
L2-003 月饼 (25 分)
知识点:贪心
注意要将种类数和需求数都开成double,不然会被卡一个点
#include<bits/stdc++.h>
#define debug(x,y) printf("%s = %d\n",x,y);
typedef long long ll;
using namespace std;
inline int read(){int s=0,w=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();//s=(s<<3)+(s<<1)+(ch^48);return s*w;
}
const int maxn=2000;
//int num[maxn];
//int val[maxn];
struct node{double num,val;double ave;
}a[maxn];
bool cmp(node a,node b){return a.val*b.num>b.val*a.num;
}
int main()
{int n,d;cin>>n>>d;for(int i=1;i<=n;i++)cin>>a[i].num;for(int i=1;i<=n;i++)cin>>a[i].val;for(int i=1;i<=n;i++)a[i].ave=1.0*a[i].val/a[i].num;sort(a+1,a+1+n,cmp);double sum=0;for(int i=1;i<=n;i++){
// cout<<a[i].ave<<endl;if(d>=a[i].num){d-=a[i].num;sum+=a[i].val;}else {sum+=d*a[i].ave;break;}}printf("%.2f\n",sum);
}
L2-004 这是二叉搜索树吗? (25 分)
知识点:考察了前序遍历和后序遍历的应用
#include<bits/stdc++.h>
#define debug(x,y) printf("%s = %d\n",x,y);
typedef long long ll;
using namespace std;
inline int read(){int s=0,w=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();//s=(s<<3)+(s<<1)+(ch^48);return s*w;
}
const int maxn=2000;
int pos[maxn];
int iff=0;
vector<int>post;
void getpos(int l,int r){if(l>r)return ;int tl=l+1,tr=r;if(!iff){//正常的二叉搜索树 while(tl<=r&&pos[tl]<pos[l])tl++;//找到第一个大的 while(tr>l&&pos[tr]>=pos[l])tr--; //找到第一个小的 }else {//镜像的 while(tl<=r&&pos[tl]>=pos[l])tl++;while(tr>l&&pos[tr]<pos[l])tr--; }if(tl!=tr+1)return ;getpos(l+1,tr);getpos(tl,r);
// cout<<pos[l]<<endl; post.push_back(pos[l]);
}
int main()
{int n;cin>>n;for(int i=1;i<=n;i++)cin>>pos[i]; getpos(1,n);if(post.size()!=n){iff=1;post.clear();getpos(1,n);}if(post.size()!=n){cout<<"NO"<<endl;return 0;}cout<<"YES"<<endl;for(int i=0;i<n;i++){if(i==0)printf("%d",post[i]);else printf(" %d",post[i]);}return 0;
}
L2-005 集合相似度 (25 分)
知识点:考察对set的应用情况
#include<bits/stdc++.h>
#define debug(x,y) printf("%s = %d\n",x,y);
typedef long long ll;
using namespace std;
inline int read(){int s=0,w=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();//s=(s<<3)+(s<<1)+(ch^48);return s*w;
}
set<int>s[100];
int main()
{int n;cin>>n;for(int i=1;i<=n;i++){int num;cin>>num;for(int j=1;j<=num;j++){int x;cin>>x;s[i].insert(x);}}cin>>n;for(int i=1;i<=n;i++){int x,y;cin>>x>>y;int size1=s[x].size();int size2=s[y].size();int size3=0;for(set<int>::iterator it=s[x].begin();it!=s[x].end();it++){if(s[y].find(*it)!=s[y].end()){size3++;}}
// printf("size3=%d\n",size3);printf("%.2lf%%\n",1.0*size3/(size1+size2-size3)*100);}
}
L2-006 树的遍历 (25 分)
知识点:考察了如何通过后序遍历和中序遍历确定树的结构,并用代码实现
#include<bits/stdc++.h>
#define debug(x,y) printf("%s = %d\n",x,y);
typedef long long ll;
using namespace std;
inline int read(){int s=0,w=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();//s=(s<<3)+(s<<1)+(ch^48);return s*w;
}
const int maxn=50;
int post[maxn];
int mid[maxn];
struct node{int l,r;
}tr[maxn<<2];
int build(int lmid,int rmid,int lpost,int rpost){/*后序:前后中 中序:前中后 */if(lmid>rmid)return 0;int root=post[rpost];int fa=lmid;while(mid[fa]!=root)fa++;//确定根int len=fa-lmid;//左子树长度 tr[root].l=build(lmid,fa-1,lpost,lpost+len-1);tr[root].r=build(fa+1,rmid,lpost+len,rpost-1);return root;
}
void bfs(int x){queue<int>q;vector<int>v;q.push(x);while(!q.empty()){int w=q.front();q.pop();if(w==0)break;v.push_back(w);if(tr[w].l)q.push(tr[w].l);if(tr[w].r)q.push(tr[w].r);}int len=v.size();for(int i=0;i<len;i++){if(i==0)cout<<v[i];else cout<<" "<<v[i];}
}
int main()
{int n;cin>>n;for(int i=1;i<=n;i++){cin>>post[i];}for(int i=1;i<=n;i++){cin>>mid[i];}int root=post[n];build(1,n,1,n);bfs(root);return 0;
}
L3-001 凑零钱
知识点:背包问题,dp[i]表示所能凑出的小于等于i的最多的钱,也就是如果dp[m]!=m说明就凑不出
#include<bits/stdc++.h>
#define debug(x,y) printf("%s = %d\n",x,y);
typedef long long ll;
using namespace std;
inline int read(){int s=0,w=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();//s=(s<<3)+(s<<1)+(ch^48);return s*w;
}
const int maxn=2e4+9;
int a[maxn];
int dp[maxn];
int vis[maxn][maxn];
int main()
{int n,m;cin>>n>>m;for(int i=1;i<=n;i++)cin>>a[i];sort(a+1,a+1+n,greater<int>());for(int i=1;i<=n;i++){for(int j=m;j>=a[i];j--){if(dp[j]<=dp[j-a[i]]+a[i]){vis[i][j]=1;dp[j]=dp[j-a[i]]+a[i];}}}if(dp[m]!=m){printf("No Solution\n");return 0;}int i=n;int j=m;while(j>0){if(vis[i][j]){if(j==m){printf("%d",a[i]);}else printf(" %d",a[i]);j-=a[i];}i--;}return 0;
}
L3-002 特殊堆栈
知识点:是否熟练使用vector的各种操作
#include <cstdio>
#include <vector>
#include <algorithm>
#include <cstring>
#include <string>
#include <algorithm>
#include<bits/stdc++.h>
using namespace std;
int main()
{int n;vector<int> v1,v;scanf("%d",&n);vector<int>::iterator it;while(n--){string s;cin>>s; if(s == "Push"){int temp;scanf("%d",&temp);v1.push_back(temp);it = lower_bound(v.begin(),v.end(),temp);v.insert(it,temp);}else if(s == "Pop"){if(v1.size() == 0)printf("Invalid\n");else {it = find(v.begin(),v.end(),v1[v1.size()-1]);v.erase(it);printf("%d\n",v1[v1.size()-1]);v1.pop_back();}}else if(s == "PeekMedian"){if(v1.size() == 0){printf("Invalid\n");continue;}if(v.size() % 2 == 0)printf("%d\n",v[v.size()/2-1]);elseprintf("%d\n",v[v.size()/2]);}}return 0;
}
L3-003 社交集群 (30 分)
#include <bits/stdc++.h>
#include <unordered_map>
#define debug(a, b) printf("%s = %d\n", a, b);
using namespace std;
bool Handsome;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> PII;
clock_t startTime, endTime;
//Fe~Jozky
const ll INF_ll= 1e18;
const int INF_int= 0x3f3f3f3f;
void read(){};
template <typename _Tp, typename... _Tps> void read(_Tp& x, _Tps&... Ar)
{x= 0;char c= getchar();bool flag= 0;while (c < '0' || c > '9')flag|= (c == '-'), c= getchar();while (c >= '0' && c <= '9')x= (x << 3) + (x << 1) + (c ^ 48), c= getchar();if (flag)x= -x;read(Ar...);
}
template <typename T> inline void write(T x)
{if (x < 0) {x= ~(x - 1);putchar('-');}if (x > 9)write(x / 10);putchar(x % 10 + '0');
}
void rd_test(bool &Most)
{
#ifdef ONLINE_JUDGE
#elseprintf("%.2lfMB\n",(&Most-&Handsome)/1024.0/1024.0);startTime = clock ();freopen("data.in", "r", stdin);
#endif
}
void Time_test()
{
#ifdef ONLINE_JUDGE
#elseendTime= clock();printf("\nRun Time:%lfs\n", (double)(endTime - startTime) / CLOCKS_PER_SEC);
#endif
}
bool Most;
const int maxn=3e3+9;
int fa[maxn];
int find(int x){if(fa[x]!=x)return fa[x]=find(fa[x]);return fa[x];
}
void unionn(int x,int y){int fx=find(x);int fy=find(y);if(fx!=fy)fa[fx]=fy;
}
int vis[maxn];
vector<int>vec;
int a[maxn];
int main()
{//rd_test(Most);int n;read(n);for(int i=1;i<=2000;i++)fa[i]=i;for(int i=1;i<=n;i++){int m,x;scanf("%d:%d",&m,&a[i]);for(int j=1;j<m;j++){int y;read(y);unionn(a[i],y);}}for(int i=1;i<=n;i++){int x=find(a[i]);
// printf("x=%d\n",x);vis[x]++;}for(int i=1;i<=1000;i++){if(vis[i]){
// printf("i=%d\n",i);vec.push_back(vis[i]);}}sort(vec.begin(),vec.end());printf("%d\n",vec.size());for(int i=vec.size()-1;i>=0;i--){if(i!=0)cout<<vec[i]<<" ";else cout<<vec[i];}//Time_test();
}