Codeforces Beta Round #67 (Div. 2)
http://codeforces.com/contest/75
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 pb push_back 7 #define eb emplace_back 8 #define maxn 1000006 9 #define eps 1e-8 10 #define pi acos(-1.0) 11 #define rep(k,i,j) for(int k=i;k<j;k++) 12 typedef long long ll; 13 typedef unsigned long long ull; 14 15 16 int main(){ 17 #ifndef ONLINE_JUDGE 18 // freopen("input.txt","r",stdin); 19 #endif 20 std::ios::sync_with_stdio(false); 21 int a,b,c; 22 cin>>a>>b; 23 c=a+b; 24 int ccc=0; 25 int aa=0,bb=0,cc; 26 int p=1; 27 while(a){ 28 int tmp=a%10; 29 if(tmp!=0){ 30 aa+=(tmp)*p; 31 p*=10; 32 } 33 a/=10; 34 } 35 p=1; 36 while(b){ 37 int tmp=b%10; 38 if(tmp!=0){ 39 bb+=(tmp)*p; 40 p*=10; 41 } 42 b/=10; 43 } 44 p=1; 45 while(c){ 46 int tmp=c%10; 47 if(tmp!=0){ 48 ccc+=(tmp)*p; 49 p*=10; 50 } 51 c/=10; 52 } 53 cc=aa+bb; 54 if(cc==ccc) cout<<"YES"<<endl; 55 else cout<<"NO"<<endl; 56 }
B
模拟
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 pb push_back 7 #define eb emplace_back 8 #define maxn 1000006 9 #define eps 1e-8 10 #define pi acos(-1.0) 11 #define rep(k,i,j) for(int k=i;k<j;k++) 12 typedef long long ll; 13 typedef unsigned long long ull; 14 15 16 int main(){ 17 #ifndef ONLINE_JUDGE 18 // freopen("input.txt","r",stdin); 19 #endif 20 std::ios::sync_with_stdio(false); 21 string me; 22 cin>>me; 23 int n; 24 cin>>n; 25 map<string,int>M,S{{"posted",15},{"commented",10},{"likes",5}}; 26 for(string a,b,c,x;cin>>a>>b>>c>>x;M[a],M[c]) 27 { 28 if(c=="on")c=x,cin>>x; 29 c.pop_back();c.pop_back(); 30 if(a==me)M[c]+=S[b]; 31 if(c==me)M[a]+=S[b]; 32 } 33 vector<pair<int,string>>V; 34 for(map<string,int>::iterator it=M.begin();it!=M.end();it++)V.emplace_back(-it->second,it->first); 35 sort(V.begin(),V.end()); 36 for(int i=0;i<V.size();i++)if(V[i].second!=me)cout<<V[i].second<<endl; 37 }
C
二分+gcd
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 pb push_back 7 #define eb emplace_back 8 #define maxn 1000006 9 #define eps 1e-8 10 #define pi acos(-1.0) 11 #define rep(k,i,j) for(int k=i;k<j;k++) 12 typedef long long ll; 13 typedef unsigned long long ull; 14 15 int aa,bb,l,r,x,y; 16 int a[100005]; 17 18 int main(){ 19 #ifndef ONLINE_JUDGE 20 // freopen("input.txt","r",stdin); 21 #endif 22 std::ios::sync_with_stdio(false); 23 cin>>aa>>bb; 24 int n; 25 cin>>n; 26 int gcd=__gcd(aa,bb); 27 int co=1; 28 int gg=sqrt(gcd); 29 a[co++]=1; 30 for(int i=2;i<=gg;i++){ 31 if(gcd%i==0){ 32 a[co++]=i; 33 if(gcd/i!=gg){ 34 a[co++]=gcd/i; 35 } 36 } 37 } 38 a[co++]=gcd; 39 sort(a+1,a+co); 40 int mid; 41 for(int i=1;i<=n;i++){ 42 cin>>x>>y; 43 l=1,r=co-1; 44 while(l<=r){ 45 mid=l+r>>1; 46 if(a[mid]<=y) l=mid+1; 47 else { 48 r=mid-1; 49 } 50 } 51 if(a[r]>y) r--; 52 if(a[r]>=x&&a[r]<=y) cout<<a[r]<<endl; 53 else cout<<-1<<endl; 54 } 55 }
D
应该是最大子段和的加强版吧，把最大前缀和，最大后缀和，最大子区间和求出来，然后找最大值
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 pb push_back 7 #define eb emplace_back 8 #define maxn 1000006 9 #define eps 1e-8 10 #define pi acos(-1.0) 11 #define rep(k,i,j) for(int k=i;k<j;k++) 12 typedef long long ll; 13 typedef unsigned long long ull; 14 15 ll maxl[55],maxr[55],sum[55],dp[55],Right; 16 17 int main(){ 18 #ifndef ONLINE_JUDGE 19 // freopen("input.txt","r",stdin); 20 #endif 21 std::ios::sync_with_stdio(false); 22 int n,m; 23 cin>>n>>m; 24 int num; 25 int x; 26 for(int i=1;i<=n;i++){ 27 cin>>num; 28 maxl[i]=dp[i]=-0x3f3f3f3f; 29 Right=0; 30 for(int j=1;j<=num;j++){ 31 cin>>x; 32 sum[i]+=x; 33 maxl[i]=max(sum[i],maxl[i]); 34 Right+=x; 35 dp[i]=max(dp[i],Right); 36 if(Right<0) Right=0; 37 } 38 maxr[i]=Right; 39 } 40 ll ans=-0x3f3f3f3f; 41 Right=0; 42 for(int i=1;i<=m;i++){ 43 cin>>x; 44 ans=max(max(ans,dp[x]),Right+maxl[x]); 45 Right=max(Right+sum[x],maxr[x]); 46 } 47 cout<<ans<<endl; 48 }
E
几何，分类讨论即可
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 pb push_back 7 #define eb emplace_back 8 #define maxn 1000006 9 #define eps 1e-8 10 #define pi acos(-1.0) 11 #define rep(k,i,j) for(int k=i;k<j;k++) 12 typedef long long ll; 13 typedef unsigned long long ull; 14 15 struct Point{ 16 double x,y; 17 }a[105],h[105],s,e; 18 double ans; 19 int p[105],n,m; 20 21 double dis(Point a, Point b) { 22 return sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y)); 23 } 24 25 double cross(Point s, Point a, Point b) { 26 return (a.x - s.x) * (b.y - s.y) - (b.x - s.x) * (a.y - s.y); 27 } 28 29 void check(Point a, Point b, Point c, Point d, int i) { 30 double t1 = cross(a, c, b), t2 = cross(a, b, d), t3 = cross(c, a, d), t4 = cross(c, d, b); 31 if (fabs(t1) < eps && fabs(t2) < eps) return ; 32 if (fabs(dis(a, c) + dis(c, b) - dis(a, b)) < eps) { 33 h[m] = c; p[m] = i; ++m; return ; 34 } 35 if (t1 * t2 > eps && t3 * t4 > eps) { 36 h[m].x = (t1 * d.x + t2 * c.x) / (t1 + t2); 37 h[m].y = (t1 * d.y + t2 * c.y) / (t1 + t2); 38 p[m] = i; ++m; 39 } 40 } 41 42 double getl(int st, int en, int x, int y) { 43 double res; st = (st + 1) % n; res = 0; 44 for (int i = st; i != en; i = (i + 1) % n) 45 res += dis(a[i], a[(i + 1) % n]); 46 return res + dis(h[x], a[st]) + dis(a[en], h[y]); 47 } 48 49 50 int main(){ 51 #ifndef ONLINE_JUDGE 52 // freopen("input.txt","r",stdin); 53 #endif 54 // std::ios::sync_with_stdio(false); 55 cin>>s.x>>s.y>>e.x>>e.y>>n; 56 for (int i = 0; i < n; ++i) cin>>a[i].x>>a[i].y; 57 for (int i = 0; i < n; ++i) check(s, e, a[i], a[(i + 1) % n], i); 58 if (m == 2) { 59 if (dis(s, h[0]) > dis(s, h[1])) swap(h[0], h[1]), swap(p[0], p[1]); 60 ans = min(getl(p[0], p[1], 0, 1), getl(p[1], p[0], 1, 0)); 61 ans = min(ans, dis(h[0], h[1]) * 2); 62 ans += dis(s, h[0]) + dis(h[1], e); 63 } 64 else ans = dis(s, e); 65 printf("%.7f ",ans); 66 }