[思路题 乱搞] BZOJ 4377 [POI2015]Kurs szybkiego czytania

%%% Claris ：http://www.cnblogs.com/clrs97/p/5131958.html

每个ai是互不相同的

所以在以ai为下标的一个表删一些区间，剩余的就是解

#include<cstdio>#include<cstdlib>#include<algorithm>using namespace std;inline char nc(){static char buf[100000],*p1=buf,*p2=buf;if (p1==p2) { p2=(p1=buf)+fread(buf,1,100000,stdin); if (p1==p2) return EOF; }return *p1++;}inline void read(int &x){char c=nc(),b=1;for (;!(c>='0' && c<='9');c=nc()) if (c=='-') b=-1;for (x=0;c>='0' && c<='9';x=x*10+c-'0',c=nc()); x*=b;}inline void read(char *s){char c=nc(); int len=0;for (;!(c=='0' || c=='1');c=nc());for (;c=='0' || c=='1';s[++len]=c,c=nc()); s[++len]=0;}struct edge{int x,y;edge(int x=0,int y=0):x(x),y(y) {} bool operator < (const edge &B) const{return x<B.x;}}E[4000005];int cnt;int n,m,A,B,P;char w[1000005];inline void add(int a,int b,int c,int d){if(a)E[++cnt]=edge(0,a);if(b<c)E[++cnt]=edge(b,c);if(d<n)E[++cnt]=edge(d,n);}int main(){freopen("t.in","r",stdin);freopen("t.out","w",stdout);read(n); read(A); read(B); read(P); read(m);read(w);for (int i=1;i<=m;i++,(B+=A)%=n)if (w[i]=='0')add(0,max(P-B,0),n-B,min(P-B+n,n));else add(max(P-B,0),n-B,min(P-B+n,n),n);B=n-A;for(int i=n-1;i>n-m;B=(B-A+n)%n,i--)E[++cnt]=edge(B,B+1);E[++cnt]=edge(n,n+1);sort(E+1,E+cnt+1);int ans=0,r=0;for (int i=1;i<=cnt;i++){    if(E[i].x>r) ans+=E[i].x-r;    if(E[i].y>r) r=E[i].y;  }printf("%d\n",ans);  return 0;}