0×02 枚举,模拟,递推
$Poj1958 Stange Towers of Hanoi$
递推
View Code#include<iostream> #include<cstdio> #define il inline #define Rg register #define go(i,a,b) for(Rg int i=a;i<=b;i++) #define yes(i,a,b) for(Rg int i=a;i>=b;i++) #define inf 2100000000 using namespace std; int n,d[20],f[20]; int main() { d[1]=f[1]=1;printf("1 "); go(i,2,12)f[i]=inf; go(n,2,12) { d[n]=2*d[n-1]+1; go(i,1,n-1)f[n]=min(f[n],2*f[i]+d[n-i]); printf("%d ",f[n]); } return 0; }
$BZOJ2018 激光炸弹$
前缀和
View Code1 #include<iostream> 2 #include<cstdio> 3 #define il inline 4 #define Rg register 5 #define go(i,a,b) for(Rg int i=a;i<=b;i++) 6 #define yes(i,a,b) for(Rg int i=a;i>=b;i++) 7 using namespace std; 8 il int read() 9 { 10 int x=0,y=1;char c=getchar(); 11 while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();} 12 while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+c-'0';c=getchar();} 13 return x*y; 14 } 15 int n,r,l1,l2,ans,f[5002][5002]; 16 int main() 17 { 18 n=read(),r=read(); 19 go(i,1,n) 20 { 21 int x=read()+1,y=read()+1; 22 l1=max(l1,x),l2=max(l2,y); 23 f[x][y]=read(); 24 } 25 go(i,1,l1) 26 go(j,1,l2) 27 { 28 f[i][j]=f[i-1][j]+f[i][j-1]-f[i-1][j-1]+f[i][j]; 29 int h=max(i-r,0),k=max(j-r,0); 30 ans=max(ans,f[i][j]-f[h][j]-f[i][k]+f[h][k]); 31 } 32 printf("%d ",ans); 33 return 0; 34 }
$Poj3263 Tallest Cow$
只讲一下优化：把对一个区间的操作转化为左,右两个端点上的操作,再通过前缀和得到原问题的解。
View Code#include<iostream> #include<cstdio> #include<map> #define il inline #define Rg register #define go(i,a,b) for(Rg int i=a;i<=b;i++) #define yes(i,a,b) for(Rg int i=a;i>=b;i++) using namespace std; il int read() { int x=0,y=1;char c=getchar(); while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();} while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+c-'0';c=getchar();} return x*y; } map<pair<int,int>,bool> f; int N,I,H,R,A,B,a[10001],b[10001]; int main() { N=read(),I=read(),H=read(),R=read(); go(i,1,R) { A=read(),B=read();if(A>B)swap(A,B); if(f[make_pair(A,B)])continue; a[A+1]-=1;a[B]+=1;f[make_pair(A,B)]=1; } go(i,1,N){b[i]=b[i-1]+a[i];printf("%d ",H+b[i]);} return 0; }
0×03 递归
$Poj1845 Sumdiv$
分治！
View Code1 #include<iostream> 2 #include<cstdio> 3 #define il inline 4 #define Rg register 5 #define go(i,a,b) for(Rg int i=a;i<=b;i++) 6 #define yes(i,a,b) for(Rg int i=a;i>=b;i++) 7 #define ll long long 8 using namespace std; 9 il int read() 10 { 11 int x=0,y=1;char c=getchar(); 12 while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();} 13 while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+c-'0';c=getchar();} 14 return x*y; 15 } 16 const int N=20,mod=9901; 17 int n,m,ct,a[N],b[N]; 18 ll ans=1; 19 il void brk(int x) 20 { 21 for(Rg int i=2;i*i<=x;i++) 22 { 23 if(x%i==0)a[++ct]=i; 24 while(x%i==0)x/=i,b[ct]++; 25 } 26 if(x>1)a[++ct]=x,b[ct]++; 27 } 28 il ll ksm(int x,int y) 29 { 30 ll ret=1;x%=mod;//remember to mod !!!!!!! 31 while(y){if(y&1)ret=ret*x%mod;x=x*x%mod;y>>=1;} 32 return ret; 33 } 34 il ll sum(int p,int c) 35 { 36 if(!c)return 1; 37 if(c&1)return (ksm(p,(c+1)>>1)+1)*sum(p,(c-1)/2)%mod; 38 else return ((ksm(p,c>>1)+1)*sum(p,(c/2-1))%mod+ksm(p,c))%mod; 39 } 40 int main() 41 { 42 n=read(),m=read(); 43 brk(n); 44 go(i,1,ct){ans=(ans*sum(a[i],b[i]*m))%mod;} 45 printf("%lld ",ans); 46 return 0; 47 }
$Poj3889 Fractal Streets$
递归 $remember to be careful!$
View Code#include<iostream> #include<cstdio> #include<cmath> #define il inline #define Rg register #define go(i,a,b) for(Rg int i=a;i<=b;i++) #define yes(i,a,b) for(Rg int i=a;i>=b;i++) #define ll long long #define db double using namespace std; int T,n; ll a,b; il ll s(ll x){return x*x;} il pair<ll,ll> calc(int n,ll x) { if(n==0)return make_pair(1,1); ll c=1LL<<(2*n-2),d=(x-1)/c,e=x%c,len=1LL<<(n-1); if(!e)e=c; pair<ll,ll> tmp=calc(n-1,e); ll f=tmp.first,g=tmp.second; if(d==0)return make_pair(g,f); if(d==1)return make_pair(f,g+len); if(d==2)return make_pair(f+len,g+len); return make_pair(len*2-g+1,len-f+1); } int main() { scanf("%d",&T); while(T--) { scanf("%d%lld%lld",&n,&a,&b); pair<ll,ll> aa,bb; aa=calc(n,a);bb=calc(n,b); db ans=sqrt((db)(s(aa.first-bb.first)+s(aa.second-bb.second)))*10; printf("%.0lf ",ans); } return 0; }
0×04 二分
$Poj2018 Best Cow Fances$
View Code1 #include<iostream> 2 #include<cstdio> 3 #define il inline 4 #define Rg register 5 #define go(i,a,b) for(Rg int i=a;i<=b;i++) 6 #define yes(i,a,b) for(Rg int i=a;i>=b;i++) 7 #define db double 8 #define eps 1e-7 9 #define inf 2100000000 10 using namespace std; 11 il int read() 12 { 13 int x=0,y=1;char c=getchar(); 14 while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();} 15 while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+c-'0';c=getchar();} 16 return x*y; 17 } 18 int n,f; 19 db l=0,r=inf,mid,a[100001],b[100001],s[100001]; 20 il bool ck() 21 { 22 go(i,1,n)b[i]=a[i]-mid; 23 go(i,1,n)s[i]=s[i-1]+b[i]; 24 db mins=inf,maxs=-inf; 25 go(i,f,n) 26 { 27 mins=min(mins,s[i-f]); 28 maxs=max(maxs,s[i]-mins); 29 } 30 if(maxs>=0)return 1;return 0; 31 } 32 int main() 33 { 34 n=read(),f=read(); 35 go(i,1,n)scanf("%lf",&a[i]),l=min(l,a[i]),r=max(r,a[i]); 36 while(r-l>eps) 37 { 38 mid=(l+r)*1.0/2; 39 if(ck())l=mid; 40 else r=mid; 41 } 42 printf("%d ",(int)(r*1000)); 43 return 0; 44 }
0×05 排序
$CF670C Cinema$
离散化或者$map$
$CH0501 货仓选址$
$BZOJ3032 七夕祭$
$Poj2784 Running Median$
View Code#include<iostream> #include<cstdio> #include<queue> #define il inline #define Rg register #define go(i,a,b) for(Rg int i=a;i<=b;i++) #define yes(i,a,b) for(Rg int i=a;i>=b;i++) using namespace std; il int read() { int x=0,y=1;char c=getchar(); while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();} while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+c-'0';c=getchar();} return x*y; } int t,t1,n,nw; priority_queue<int>q1; priority_queue<int,vector<int>,greater<int> >q2; int main() { t=read(); while(t--) { t1=read(),n=read();printf("%d %d ",t1,n/2+1); while(q1.size()>0)q1.pop(); while(q2.size()>0)q2.pop(); go(i,1,n) { int x=read(); if(i==1){nw=x;q2.push(x);} else { if(x<nw)q1.push(x); else q2.push(x); } while((int)q1.size()>(int)q2.size()){int y=q1.top();q1.pop();q2.push(y);} if((int)q2.size()-(int)q1.size()>1){int y=q2.top();q2.pop();q1.push(y);} nw=q2.top(); if(i&1)printf("%d ",nw); if((i&1)&&(i/2+1)%10==0)printf(" "); } if((n/2+1)%10)printf(" "); } return 0; }
$Poj2299 Ultra-QuikSort$
View Code#include<iostream> #include<cstdio> #define il inline #define Rg register #define go(i,a,b) for(Rg int i=a;i<=b;i++) #define yes(i,a,b) for(Rg int i=a;i>=b;i++) #define ll long long using namespace std; il int read() { int x=0,y=1;char c=getchar(); while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();} while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+c-'0';c=getchar();} return x*y; } const int N=500001; int n,a[N],b[N]; ll as; il void sol(int l,int r) { if(l==r)return; int mid=(l+r)>>1; sol(l,mid);sol(mid+1,r); Rg int i=l,j=mid+1; go(k,l,r) { if((a[i]<a[j]&&i<=mid) || j>r)b[k]=a[i++]; else b[k]=a[j++],as+=mid-i+1; } go(k,l,r)a[k]=b[k]; } int main() { while(1) { n=read();as=0; if(!n)break; go(i,1,n)a[i]=read(); sol(1,n); printf("%lld ",as); } return 0; }
0×06 倍增
$CH0601 Genius ACM$
View Code#include<iostream> #include<cstdio> #include<algorithm> #define il inline #define Rg register #define go(i,a,b) for(Rg int i=a;i<=b;i++) #define yes(i,a,b) for(Rg int i=a;i>=b;i++) #define ll long long using namespace std; il int read() { int x=0,y=1;char c=getchar(); while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();} while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+c-'0';c=getchar();} return x*y; } int T,n,m,as,a[500001],b[500001],c[500001]; ll K; il bool ck(int l,int r,int md) { go(i,md,r)b[i]=a[i]; sort(b+md,b+r+1); int i=l,j=md; go(k,l,r) if((i<=md-1 && b[i]<b[j]) || j>r)c[k]=b[i++]; else c[k]=b[j++]; i=l,j=r;int t=min(m,(r-l+1)/2);ll nw=0; while(t--) nw+=1LL*(c[i]-c[j])*(c[i]-c[j]),i++,j--; if(nw<=K) { go(i,l,r)b[i]=c[i]; return 1; } return 0; } int main() { T=read(); while(T--) { n=read(),m=read();scanf("%lld",&K);as=0; go(i,1,n)a[i]=read(); int l=1,r=1,p=1; b[1]=a[1]; while(l<=n) { if(r+p<=n && ck(l,r+p,r+1))r+=p,p*=2; else p/=2; if(!p || r==n){as++,l=++r,p=1,b[l]=a[l];} } printf("%d ",as); } return 0; }
0×07 贪心
$Poj3614 Sunscreen$
View Code#include<iostream> #include<cstdio> #include<algorithm> #define il inline #define Rg register #define go(i,a,b) for(Rg int i=a;i<=b;i++) #define yes(i,a,b) for(Rg int i=a;i>=b;i--) using namespace std; il int read() { int x=0,y=1;char c=getchar(); while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();} while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+c-'0';c=getchar();} return x*y; } int n,m,as,b[1001]; struct node{int l,r;}a[2501]; il bool cmp(node x,node y){return x.l>y.l;} int main() { n=read(),m=read(); go(i,1,n)a[i].l=read(),a[i].r=read(); go(i,1,m){int x=read(),y=read();b[x]+=y;} sort(a+1,a+n+1,cmp); go(i,1,n) { int l=a[i].l,r=a[i].r; yes(j,r,l)if(b[j]>0){b[j]--;as++;break;} } printf("%d ",as); return 0; }
$Poj3190 Stall Reservation$
View Code#include<iostream> #include<cstdio> #include<algorithm> #include<queue> #define il inline #define Rg register #define pr pair<int,int> #define mp make_pair #define go(i,a,b) for(Rg int i=a;i<=b;i++) #define yes(i,a,b) for(Rg int i=a;i>=b;i++) using namespace std; il int read() { int x=0,y=1;char c=getchar(); while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();} while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+c-'0';c=getchar();} return x*y; } int n,cl[50001],ct; struct node{int l,r,pos;}a[50001]; priority_queue<pr,vector<pr>,greater<pr> >q; il bool cmp(node x,node y){return x.l<y.l;} int main() { n=read(); go(i,1,n)a[i].l=read(),a[i].r=read(),a[i].pos=i;; sort(a+1,a+n+1,cmp); q.push(mp(a[1].r,a[1].pos));cl[a[1].pos]=++ct; go(i,2,n) { pr t=q.top(); if(a[i].l>t.first){q.pop();q.push(mp(a[i].r,a[i].pos));cl[a[i].pos]=cl[t.second];} else{q.push(mp(a[i].r,a[i].pos));cl[a[i].pos]=++ct;} } printf("%d ",ct); go(i,1,n)printf("%d ",cl[i]); return 0; }
$Poj1328 Radar Installation$
View Code#include<iostream> #include<cstdio> #include<cmath> #include<algorithm> #define il inline #define Rg register #define go(i,a,b) for(Rg int i=a;i<=b;i++) #define yes(i,a,b) for(Rg int i=a;i>=b;i--) #define ll long long #define db double using namespace std; il int read() { int x=0,y=1;char c=getchar(); while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();} while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+c-'0';c=getchar();} return x*y; } int n,d,as; db nw; struct node{db l,r;}a[1001]; il bool cmp(node x,node y){return x.l<y.l;} int main() { n=read(),d=read();nw=-1e9-1e9; go(i,1,n) { int x,y;x=read(),y=read(); if(y>d){printf("-1 ");return 0;} db r=sqrt((db)(d*d-y*y)); a[i].l=x-r,a[i].r=x+r; } sort(a+1,a+n+1,cmp); go(i,1,n) { if(a[i].l<=nw){nw=min(nw,a[i].r);} else {as++,nw=a[i].r;} } printf("%d ",as); return 0; }
$Poj2054 Color a Tree$
View Code#include<iostream> #include<cstdio> #define il inline #define Rg register #define go(i,a,b) for(Rg int i=a;i<=b;i++) #define yes(i,a,b) for(Rg int i=a;i>=b;i++) #define db double #define ll long long using namespace std; il int read() { int x=0,y=1;char c=getchar(); while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();} while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+c-'0';c=getchar();} return x*y; } int n,rt,a[1001],fa[1001],s[1001]; ll as; int main() { while(1) { n=read(),rt=read();as=0; if(!n && !rt)return 0; go(i,1,n)a[i]=read(),s[i]=1; go(i,1,n-1){int x=read(),y=read();fa[y]=x;} go(T,1,n-1) { db maxs=0;int pos; go(i,1,n) if(i!=rt && 1.0*a[i]/s[i]>=maxs)maxs=1.0*a[i]/s[i],pos=i; go(i,1,n) if(fa[i]==pos)fa[i]=fa[pos]; as+=a[pos]*s[fa[pos]]; s[fa[pos]]+=s[pos]; a[fa[pos]]+=a[pos]; a[pos]=0; } as+=a[rt]; printf("%lld ",as); } return 0; }