238 lines
6.8 KiB
C++
238 lines
6.8 KiB
C++
#include<iostream>
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#include<cstring>
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#include<algorithm>
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#include<cassert>
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#include<cstdio>
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#define unlikely(x) __builtin_expect(!!(x), 0)
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struct char_reader
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{
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FILE* f; char *buf,*p1,*p2; int size;
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char_reader(FILE* fin,int bufsize=1<<16) { f=fin; size=bufsize; p1=p2=0; buf=new char[size]; }
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~char_reader() { delete []buf; }
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inline int operator()() { return p1==p2&&(p2=(p1=buf)+fread(buf,1,size,f),p1==p2)?EOF:*p1++; }
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};
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struct char_writer
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{
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FILE* f; char *buf,*p,*end; int size;
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char_writer(FILE* fout,int bufsize=1<<16) { f=fout; size=bufsize; buf=new char[size]; p=buf; end=buf+bufsize; }
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~char_writer() { fwrite(buf,p-buf,1,f); delete []buf; }
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inline char operator()(char ch)
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{
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if(unlikely(end==p)) { fwrite(buf,end-buf,1,f); p=buf; }
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return *p++=ch;
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}
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};
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char_reader gch(stdin);
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char_writer wch(stdout);
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template<typename T> inline int read(T& t)
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{
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bool f=false; int ch; while(ch=gch(),!((ch>='0'&&ch<='9')||ch=='-')) { if(ch==EOF) return 0; }
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t=0;
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if(ch=='-') f=true,ch=gch(); t=ch^48; while(ch=gch(),ch>='0'&&ch<='9') t=(t<<3)+(t<<1)+(ch^48);
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if(f) t=-t;
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return 1;
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}
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inline int read(char &c)
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{
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c=0; int ch; while(ch=gch(),(ch==' '||ch=='\n'||ch=='\r'||ch=='\t')) { if(ch==EOF) return 0; } c=ch;
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return 1;
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}
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inline int read(char *s)
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{
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int ch; while(ch=gch(),(ch==' '||ch=='\n'||ch=='\r'||ch=='\t')) { if(ch==EOF) return 0; }
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*s++=ch; while(ch=gch(),!(ch==' '||ch=='\n'||ch=='\r'||ch=='\t')&&ch!=EOF) *s++=ch;
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return 1;
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} inline int read(const char *s) { return read((char*)s); }
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inline int readline(char *s)
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{
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int ch; while(ch=gch(),(ch==' '||ch=='\n'||ch=='\r'||ch=='\t')) { if(ch==EOF) return 0; }
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*s++=ch; while(ch=gch(),!(ch=='\n'||ch=='\r')&&ch!=EOF) *s++=ch;
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return 1;
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} inline int readline(const char *s) { return readline((char*)s); }
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template<typename T> inline void write(T t)
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{
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int stk[20],cnt=0;
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if(t==0) { wch('0'); return; } if(t<0) { wch('-'); t=-t; }
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while(t>0) { stk[cnt++]=t%10; t/=10; } while(cnt) wch(stk[--cnt]+'0');
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}
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inline void write(char t) { wch(t); }
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inline void write(char *s) { while(*s) wch(*s++); } inline void write(const char *s) { write((char*)s); }
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#if __cplusplus >= 201103L
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template<typename T,typename... Args> inline int read(T& t,Args&... args) { return read(t)+read(args...); }
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template<typename T,typename... Args> inline void write(T t,Args... args) { write(t); write(args...); }
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#else
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template<typename A_t,typename B_t> inline int read(A_t &a,B_t &b) { return read(a)+read(b); }
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template<typename A_t,typename B_t,typename C_t> inline int read(A_t &a,B_t &b,C_t &c) { return read(a)+read(b)+read(c); }
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template<typename A_t,typename B_t,typename C_t,typename D_t> inline int read(A_t &a,B_t &b,C_t &c,D_t &d) { return read(a)+read(b)+read(c)+read(d); }
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template<typename A_t,typename B_t> inline void write(A_t a,B_t b) { write(a); write(b); }
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template<typename A_t,typename B_t,typename C_t> inline void write(A_t a,B_t b,C_t c) { write(a); write(b); write(c); }
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template<typename A_t,typename B_t,typename C_t,typename D_t> inline void write(A_t a,B_t b,C_t c,D_t d) { write(a); write(b); write(c); write(d); }
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#endif
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using namespace std;
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typedef long long LL;
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const int maxn=1e6+10;
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char s[maxn];
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class SegmentTree
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{
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struct Node
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{
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int num0;
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LL IdxSumOfZero;
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unsigned char InverseTag,RawData;
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}buf[maxn<<3]; int NodeCnt=0;
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int Length;
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unsigned char mem[maxn];
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inline void PushDown(int p,LL L,LL R)
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{
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if(buf[p].InverseTag==0) return;
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buf[p].num0=(R-L+1)-buf[p].num0;
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buf[p].InverseTag=0;
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buf[p].IdxSumOfZero=R*(R+1)/2-L*(L-1)/2-buf[p].IdxSumOfZero;
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if(L==R)
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{
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buf[p].RawData^=1;
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return;
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}
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buf[p*2].InverseTag^=1;
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buf[p*2+1].InverseTag^=1;
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}
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inline void PushUp(int p,LL L,LL R)
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{
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LL M=(L+R)>>1;
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buf[p].num0=(buf[p*2].InverseTag==0?buf[p*2].num0:M-L+1-buf[p*2].num0)
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+(buf[p*2+1].InverseTag==0?buf[p*2+1].num0:(R-(M+1)+1)-buf[p*2+1].num0);
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buf[p].IdxSumOfZero=(buf[p*2].InverseTag==0?buf[p*2].IdxSumOfZero:M*(M+1)/2-L*(L-1)/2-buf[p*2].IdxSumOfZero)
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+(buf[p*2+1].InverseTag==0?buf[p*2+1].IdxSumOfZero:R*(R+1)/2-M*(M+1)/2-buf[p*2+1].IdxSumOfZero);
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}
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void build(int p,int L,int R)
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{
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assert(L<=R);
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if(L==R)
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{
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buf[p].RawData=mem[L];
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buf[p].num0+=(mem[L]==0);
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if(mem[L]==0) buf[p].IdxSumOfZero=L;
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return;
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}
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int M=(L+R)>>1;
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build(p*2,L,M);
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build(p*2+1,M+1,R);
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PushUp(p,L,R);
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}
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int QuerySinglePointStatus(int p,int L,int R,int position)
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{
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PushDown(p,L,R);
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if(L==R) return buf[p].RawData;
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int M=(L+R)>>1;
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if(position<=M) return QuerySinglePointStatus(p*2,L,M,position);
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else return QuerySinglePointStatus(p*2+1,M+1,R,position);
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}
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void InverseBlock(int p,int BL,int BR,int OL,int OR)
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{
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PushDown(1,BL,BR);
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if(OL<=BL&&BR<=OR)
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{
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buf[p].InverseTag^=1;
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return;
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}
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int M=(BL+BR)>>1;
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if(OL<=M) InverseBlock(p*2,BL,M,OL,OR);
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if(OR>M) InverseBlock(p*2+1,M+1,BR,OL,OR);
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PushUp(p,BL,BR);
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}
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int QueryAllZero()
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{
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PushDown(1,1,Length);
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return buf[1].num0;
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}
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LL QueryIdxSumOfZeroInRange(int p,int BL,int BR,int OL,int OR)
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{
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LL res=0;
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PushDown(p,BL,BR);
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if(OL<=BL&&BR<=OR) return buf[p].IdxSumOfZero;
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int M=(BL+BR)>>1;
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if(OL<=M) res+=QueryIdxSumOfZeroInRange(p*2,BL,M,OL,OR);
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if(OR>M) res+=QueryIdxSumOfZeroInRange(p*2+1,M+1,BR,OL,OR);
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PushUp(p,BL,BR);
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return res;
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}
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public:
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void Init(char *s,int n)
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{
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Length=n;
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for(int i=1;i<=Length;i++) mem[i]=s[i-1]-'0';
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build(1,1,Length);
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}
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void InverseRange(int L,int R)
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{
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if(L>R) return;
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// for(int i=L;i<=R;i++) mem[i]^=1;
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InverseBlock(1,1,Length,L,R);
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}
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inline int NumberOfZero()
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{
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return QueryAllZero();
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// int cnt=0,tmp;
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// for(int i=1;i<=Length;i++) cnt+=(mem[i]==0);
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// if(tmp!=cnt)
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// {
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// puts("Error In NumberOfZero()");
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// printf("%d %d\n",tmp,cnt);
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// }
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// return cnt;
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}
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inline LL IdxSumOfZeroInRange(int L,int R)
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{
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if(L>R) return 0;
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return QueryIdxSumOfZeroInRange(1,1,Length,L,R);
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// LL res=0;
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// for(int i=L;i<=R;i++)
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// if(mem[i]==0)
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// res+=i;
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// return res;
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}
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inline LL IdxSumOfOneInRange(LL L,LL R)
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{
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if(L>R) return 0;
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return R*(R+1)/2-L*(L-1)/2-QueryIdxSumOfZeroInRange(1,1,Length,L,R);
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// LL res=0;
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// for(int i=L;i<=R;i++)
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// if(mem[i]==1)
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// res+=i;
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// return res;
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}
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inline char GetStatus(int position)
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{
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return '0'+QuerySinglePointStatus(1,1,Length,position);
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// return '0'+mem[position];
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}
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}SgT;
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int n,m;
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LL Solve()
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{
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LL res=0;
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int PostionOfFirstMove=SgT.NumberOfZero();
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LL Right=SgT.IdxSumOfZeroInRange(PostionOfFirstMove+1,n);
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LL Left=SgT.IdxSumOfOneInRange(1,PostionOfFirstMove-1);
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res=(Right-Left)*2;
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if(SgT.GetStatus(PostionOfFirstMove)=='0') res+=PostionOfFirstMove;
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else res-=PostionOfFirstMove;
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return res;
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}
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int main()
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{
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#ifdef local
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freopen("pro.in","r",stdin);
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#endif
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// write(212474836480ll,'\n'); return 0;
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read(n,m,s);
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SgT.Init(s,n);
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write(Solve(),'\n');
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for(int i=0;i<m;i++)
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{
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int l,r; read(l,r);
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SgT.InverseRange(l,r);
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write(Solve(),'\n');
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}
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return 0;
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} |