Codeforces Beta Round #34 (Div. 2)
http://codeforces.com/contest/34
A
1 #include<bits/stdc++.h> 2 using namespace std; 3 #define lson l,mid,rt<<1 4 #define rson mid+1,r,rt<<1|1 5 #define sqr(x) ((x)*(x)) 6 #define maxn 500005 7 typedef long long ll; 8 /*#ifndef ONLINE_JUDGE 9 freopen("1.txt","r",stdin); 10 #endif */ 11 12 int n; 13 int a[105]; 14 map<int,int>mp; 15 16 int main(){ 17 #ifndef ONLINE_JUDGE 18 // freopen("1.txt","r",stdin); 19 #endif 20 std::ios::sync_with_stdio(false); 21 int n; 22 cin>>n; 23 for(int i=1;i<=n;i++) cin>>a[i]; 24 a[n+1]=a[1]; 25 int pos1,pos2,Min=0x3f3f3f3f; 26 for(int i=1;i<=n;i++){ 27 if(abs(a[i]-a[i+1])<Min){ 28 Min=abs(a[i]-a[i+1]); 29 pos1=i; 30 pos2=i+1; 31 } 32 } 33 if(pos2==n+1) pos2=1; 34 cout<<pos1<<" "<<pos2<<endl; 35 }
B
1 #include<bits/stdc++.h> 2 using namespace std; 3 #define lson l,mid,rt<<1 4 #define rson mid+1,r,rt<<1|1 5 #define sqr(x) ((x)*(x)) 6 #define maxn 500005 7 typedef long long ll; 8 /*#ifndef ONLINE_JUDGE 9 freopen("1.txt","r",stdin); 10 #endif */ 11 12 int n; 13 int a[105]; 14 map<int,int>mp; 15 16 int main(){ 17 #ifndef ONLINE_JUDGE 18 // freopen("1.txt","r",stdin); 19 #endif 20 std::ios::sync_with_stdio(false); 21 int n; 22 int m; 23 cin>>n>>m; 24 for(int i=1;i<=n;i++) cin>>a[i]; 25 sort(a+1,a+n+1); 26 int ans=0; 27 for(int i=1;i<=n&&m;i++){ 28 if(a[i]<0){ 29 ans-=a[i]; 30 m--; 31 } 32 } 33 cout<<ans<<endl; 34 }
C
map+vector
1 #include<bits/stdc++.h> 2 using namespace std; 3 #define lson l,mid,rt<<1 4 #define rson mid+1,r,rt<<1|1 5 #define sqr(x) ((x)*(x)) 6 #define maxn 500005 7 typedef long long ll; 8 /*#ifndef ONLINE_JUDGE 9 freopen("1.txt","r",stdin); 10 #endif */ 11 12 map<int,int>mp; 13 map<int,int>::iterator it; 14 vector<int>ve; 15 16 int main(){ 17 #ifndef ONLINE_JUDGE 18 freopen("1.txt","r",stdin); 19 #endif 20 std::ios::sync_with_stdio(false); 21 string str; 22 cin>>str; 23 int co=0; 24 for(int i=0;i<str.length();i++){ 25 if(str[i]!=','){ 26 co=co*10+str[i]-'0'; 27 } 28 else{ 29 mp[co]=1; 30 co=0; 31 } 32 } 33 mp[co]=1; 34 for(it=mp.begin();it!=mp.end();it++){ 35 ve.push_back(it->first); 36 } 37 ve.push_back(0x3f3f3f3f); 38 sort(ve.begin(),ve.end()); 39 int pre=ve[0]; 40 int flag=0; 41 for(int i=0;i<ve.size()-1;i++){ 42 if(ve[i+1]-ve[i]!=1){ 43 //cout<<endl<<ve[i]<<" "<<ve[i+1]<<endl; 44 if(flag) cout<<','; 45 if(pre!=ve[i]) 46 cout<<pre<<'-'<<ve[i]; 47 else cout<<pre; 48 pre=ve[i+1]; 49 if(!flag){ 50 flag=1; 51 } 52 } 53 } 54 }
D
题意不好理解，是要求树换一个根结点后的前驱
1 #include<bits/stdc++.h> 2 using namespace std; 3 #define lson l,mid,rt<<1 4 #define rson mid+1,r,rt<<1|1 5 #define sqr(x) ((x)*(x)) 6 #define maxn 500005 7 typedef long long ll; 8 /*#ifndef ONLINE_JUDGE 9 freopen("1.txt","r",stdin); 10 #endif */ 11 12 vector<int>ve[50005]; 13 int r1,r2; 14 int n; 15 int ans[50005]; 16 int vis[50005]; 17 18 void dfs(int pos){ 19 vis[pos]=1; 20 for(int i=0;i<ve[pos].size();i++){ 21 if(!vis[ve[pos][i]]){ 22 ans[ve[pos][i]]=pos; 23 dfs(ve[pos][i]); 24 } 25 } 26 } 27 28 int main(){ 29 #ifndef ONLINE_JUDGE 30 // freopen("1.txt","r",stdin); 31 #endif 32 std::ios::sync_with_stdio(false); 33 cin>>n>>r1>>r2; 34 int a; 35 for(int i=1;i<=n;i++){ 36 if(i!=r1){ 37 cin>>a; 38 ve[i].push_back(a); 39 ve[a].push_back(i); 40 } 41 } 42 dfs(r2); 43 for(int i=1;i<=n;i++){ 44 if(i!=r2){ 45 cout<<ans[i]<<" "; 46 } 47 } 48 }