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

#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;
}