Submission #606299

#	Time	Username	Problem	Language	Result	Execution time	Memory
606299		krit3379	Fancy Fence (CEOI20_fancyfence)	C++17	0 / 100	3 ms	436 KiB

fancyfence

#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define N 100005

int n;
long long t[4*N],mi[4*N],h[N],w[N],qs[N],m,pos,mod=1e9+7,ans;

void cre(int x,int l,int r){
    if(l==r){t[x]=l,mi[x]=h[l];return ;}
    int mid=(l+r)/2;
    cre(x*2,l,mid);
    cre(x*2+1,mid+1,r);
    if(mi[x*2]<mi[x*2+1])t[x]=t[x*2];
    else t[x]=t[x*2+1];
    mi[x]=min(mi[x*2],mi[x*2+1]);
}

void query(int x,int l,int r,int ll,int rr){
    if(l>rr||ll>r||ll>rr)return ;
    if(ll<=l&&r<=rr){
        if(mi[x]<m)m=mi[x],pos=t[x];
        return ;
    }
    int mid=(l+r)/2;
    query(x*2,l,mid,ll,rr);
    query(x*2+1,mid+1,r,ll,rr);
}

void sol(int l,int r){
    if(l>r)return ;
    m=1e18;
    query(1,1,n,l,r);
    long long p=h[pos]*(h[pos]+1)/2%mod;
    ans=(ans+p*(w[pos]*(w[pos]+1)/2%mod))%mod;
    ans=(ans+p*(w[pos]*(qs[pos-1]-qs[l-1])%mod))%mod;
    ans=(ans+p*(w[pos]*(qs[r]-qs[pos])%mod))%mod;
    sol(l,pos-1),sol(pos+1,r);
}

int main(){
    int i;
    scanf("%d",&n);
    for(i=1;i<=n;i++)scanf("%lld",&h[i]);
    for(i=1;i<=n;i++)scanf("%lld",&w[i]),qs[i]=w[i]+qs[i-1];
    for(i=1;i<=n;i++)qs[i]%=mod;
    cre(1,1,n);
    sol(1,n);
    printf("%lld",ans);
    return 0;
}

Compilation message (stderr)

fancyfence.cpp: In function 'int main()':
fancyfence.cpp:44:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |     scanf("%d",&n);
      |     ~~~~~^~~~~~~~~
fancyfence.cpp:45:27: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |     for(i=1;i<=n;i++)scanf("%lld",&h[i]);
      |                      ~~~~~^~~~~~~~~~~~~~
fancyfence.cpp:46:27: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |     for(i=1;i<=n;i++)scanf("%lld",&w[i]),qs[i]=w[i]+qs[i-1];
      |                      ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 0 / 0
• Subtask 2: 0 / 12
• Subtask 3: 0 / 13
• Subtask 4: 0 / 15
• Subtask 5: 0 / 15
• Subtask 6: 0 / 18
• Subtask 7: 0 / 27