Codeforces Beta Round #7
http://codeforces.com/contest/7
A
水题
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 1000010 7 typedef long long ll; 8 /*#ifndef ONLINE_JUDGE 9 freopen("1.txt","r",stdin); 10 #endif */ 11 12 string str[15]; 13 int book[15][15]; 14 15 int Check1(int x){//lie 16 for(int i=0;i<8;i++){ 17 if(str[i][x]!='B') return 0; 18 } 19 int ans=0; 20 for(int i=0;i<8;i++){ 21 if(book[i][x]==0) book[i][x]=1,ans=1; 22 } 23 return ans; 24 } 25 26 int Check2(int x){ 27 for(int i=0;i<8;i++){ 28 if(str[x][i]!='B') return 0; 29 } 30 int ans=0; 31 for(int i=0;i<8;i++){ 32 if(book[x][i]==0) book[x][i]=1,ans=1; 33 } 34 return ans; 35 } 36 37 38 int main(){ 39 #ifndef ONLINE_JUDGE 40 freopen("1.txt","r",stdin); 41 #endif 42 std::ios::sync_with_stdio(false); 43 for(int i=0;i<8;i++) cin>>str[i]; 44 int ans=0; 45 for(int i=0;i<8;i++){ 46 ans+=Check1(i); 47 } 48 for(int i=0;i<8;i++){ 49 ans+=Check2(i); 50 } 51 cout<<ans<<endl; 52 }
B
模拟题
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 1000010 7 typedef long long ll; 8 /*#ifndef ONLINE_JUDGE 9 freopen("1.txt","r",stdin); 10 #endif */ 11 12 int t,n,m; 13 int book[105]; 14 struct sair{ 15 int first,last; 16 int flag,pos; 17 }a[105]; 18 19 bool Check(int pos){ 20 int i; 21 if(pos+n>m+1) return false; 22 for(i=pos;i<pos+n;i++){ 23 if(book[i]){ 24 return false; 25 } 26 } 27 return true; 28 } 29 30 bool cmp(sair a,sair b){ 31 if(a.flag==b.flag) 32 return a.first<b.first; 33 return a.flag>b.flag; 34 } 35 36 bool cmp2(sair a,sair b){ 37 return a.pos<b.pos; 38 } 39 40 int main(){ 41 #ifndef ONLINE_JUDGE 42 freopen("1.txt","r",stdin); 43 #endif 44 std::ios::sync_with_stdio(false); 45 cin>>t>>m; 46 string str; 47 int co=1; 48 int i; 49 for(int i=1;i<=100;i++){ 50 a[i].flag=0; 51 a[i].pos=i; 52 } 53 while(t--){ 54 cin>>str; 55 if(str=="alloc"){ 56 cin>>n; 57 for(i=1;i<=m;i++){ 58 if(Check(i)){ 59 // cout<<book[i]<<" "<<i<<"hhhhhhhhhhhhhhhhhhhhhhhhhhhhhh"<<endl; 60 a[co].first=i,a[co].last=i+n-1; 61 a[co].flag=1; 62 // cout<<a[co].first<<" "<<a[co].last<<"hhhhhhhhhhhh"<<endl; 63 for(int j=a[co].first;j<=a[co].last;j++) book[j]=1; 64 cout<<co<<endl; 65 co++; 66 break; 67 } 68 } 69 if(i==m+1){ 70 cout<<"NULL"<<endl; 71 } 72 } 73 else if(str=="erase"){ 74 cin>>n; 75 if(n<1||n>101){ 76 cout<<"ILLEGAL_ERASE_ARGUMENT"<<endl; 77 continue; 78 } 79 if(a[n].flag==0){ 80 cout<<"ILLEGAL_ERASE_ARGUMENT"<<endl; 81 } 82 else{ 83 a[n].flag=0; 84 for(i=a[n].first;i<=a[n].last;i++){ 85 book[i]=0; 86 } 87 } 88 } 89 else{ 90 memset(book,0,sizeof(book)); 91 sort(a+1,a+co,cmp); 92 int pos=1; 93 for(i=1;i<co;i++){ 94 if(a[i].flag){ 95 for(int j=a[i].first;j<=a[i].last;j++){ 96 book[pos++]=1; 97 } 98 int tmp=a[i].last-a[i].first; 99 a[i].last=pos-1; 100 a[i].first=a[i].last-tmp; 101 } 102 } 103 sort(a+1,a+co,cmp2); 104 } 105 // for(int i=1;i<=3;i++) cout<<book[i]<<" hhhhhh"<<endl; 106 } 107 }
C
扩展欧几里德模板题
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 1000010 7 typedef long long ll; 8 /*#ifndef ONLINE_JUDGE 9 freopen("1.txt","r",stdin); 10 #endif */ 11 12 void gcd(long long a,long long b,long long &d,long long &x,long long &y){ 13 if(!b){ 14 d=a; 15 x=1; 16 y=0; 17 } 18 else{ 19 gcd(b,a%b,d,y,x); 20 y-=x*(a/b); 21 } 22 } 23 int main(){ 24 #ifndef ONLINE_JUDGE 25 freopen("1.txt","r",stdin); 26 #endif 27 long long a,b,c,d,x,y; 28 scanf("%lld%lld%lld",&a,&b,&c); 29 gcd(a,b,d,x,y); 30 if(c%d) 31 printf("-1\n"); 32 else 33 printf("%lld %lld\n",-x*c/d,-y*c/d); 34 35 }
D
字符串hash（好题）
思路：把字符串的前缀正着hash和倒着hash，比较hash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 maxn 1000010 7 typedef long long ll; 8 /*#ifndef ONLINE_JUDGE 9 freopen("1.txt","r",stdin); 10 #endif */ 11 12 char str[5000005]; 13 ll dp[5000005]; 14 int main(){ 15 #ifndef ONLINE_JUDGE 16 freopen("1.txt","r",stdin); 17 #endif 18 scanf("%s",str+1); 19 ll ans=0; 20 ll t1=0,w1=0,p=121,num=1; 21 int len=strlen(str+1); 22 for(int i=1;i<=len;i++){ 23 t1=t1*p+str[i]; 24 w1=num*str[i]+w1; 25 num*=p; 26 if(t1==w1){ 27 dp[i]=dp[i/2]+1; 28 ans+=dp[i]; 29 } 30 } 31 printf("%lld\n",ans); 32 }