C45 线段树+递归合并 P4425 [HNOI/AHOI2018] 转盘

视频链接：231 线段树+递归合并 P4425 [HNOI AHOI2018] 转盘_哔哩哔哩_bilibili

 

 

 

Luogu P4425 [HNOI/AHOI2018] 转盘

// 线段树+递归合并 nlognlogn
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

#define N 200005
#define ls u<<1
#define rs u<<1|1
#define mid ((l+r)>>1)
int n,m,p,last,t[N];
int mx[N<<2],mi[N<<2];
//mx:区间最大值max{tj-j}
//mi:区间最小值min{i+max{tj-j}}

int dis(int u,int l,int r,int mrs){//求左区间mi
  if(l==r) return l+max(mx[u],mrs);
  if(mrs>=mx[rs])
    return min(mid+1+mrs,dis(ls,l,mid,mrs));
  return min(mi[u],dis(rs,mid+1,r,mrs));
}
void pushup(int u,int l,int r){ //上传
  mx[u]=max(mx[ls],mx[rs]);
  mi[u]=dis(ls,l,mid,mx[rs]);
}
void build(int u,int l,int r){  //建树
  if(l==r){mx[u]=t[l]-l,mi[u]=t[l];return;}
  build(ls,l,mid);
  build(rs,mid+1,r);
  pushup(u,l,r);
}
void change(int u,int l,int r,int x,int t){ //点修
  if(l==r){mx[u]=t-l,mi[u]=t;return;}
  if(x<=mid) change(ls,l,mid,x,t);
  else change(rs,mid+1,r,x,t);
  pushup(u,l,r);
}
int main(){
  scanf("%d%d%d",&n,&m,&p);
  for(int i=1;i<=n;++i) 
    scanf("%d",&t[i]),t[i+n]=t[i];
  build(1,1,2*n);
  printf("%d\n",last=mi[1]+n-1);
  while(m--){
    int x,y; scanf("%d%d",&x,&y);
    if(p)x^=last,y^=last;
    change(1,1,2*n,x,y);
    change(1,1,2*n,x+n,y);
    printf("%d\n",last=mi[1]+n-1);
  }
  return 0;
}