部分题解后面更行
A Equivalent Prefixes
题解：https://blog.csdn.net/liufengwei1/article/details/96515809
参考代码：
#include<bits/stdc++.h> #define maxl 100010 using namespace std; int n,ans,top; int a[maxl],b[maxl]; int la[maxl],ra[maxl],lb[maxl],rb[maxl]; int s[maxl]; inline bool jug(int mid) { top=0; for(int i=1;i<=mid;i++) { while(top>0 && a[i]<a[s[top]]) ra[s[top]]=i-1,top--; s[++top]=i; la[i]=s[top-1]+1; } while(top>0) ra[s[top]]=mid,top--; top=0; for(int i=1;i<=mid;i++) { while(top>0 && b[i]<b[s[top]]) rb[s[top]]=i-1,top--; s[++top]=i; lb[i]=s[top-1]+1; } while(top>0) rb[s[top]]=mid,top--; for(int i=1;i<=mid;i++) if(la[i]!=lb[i] || ra[i]!=rb[i]) return false; return true; } int main() { while(~scanf("%d",&n)) { for(int i=1;i<=n;i++) scanf("%d",&a[i]); for(int i=1;i<=n;i++) scanf("%d",&b[i]); int l=1,r=n,mid; while(l+1<r) { mid=(l+r)>>1; if(jug(mid)) l=mid; else r=mid; } if(jug(r)) ans=r; else ans=l; printf("%d\n",ans); } return 0; }