Submission #1272997

#	Time	Username	Problem	Language	Result	Execution time	Memory
1272997		hihihihaw	Fancy Fence (CEOI20_fancyfence)	C++20	0 / 100	2 ms	580 KiB

fancyfence

#pragma GCC optimize("O3,unroll-loops")    
#include <bits/stdc++.h>
using namespace std;
 
#define int long long
#define pb push_back
#define pii pair<int,int>
#define sz(v) (int)v.size()
#define fi first
#define se second
#define INF 1223372036854775807
#define INF2 122337203
#define MOD 1000000007
#define cint(x) int x;cin>>x;
#define cinarr(a,n) int a[n];for (int i=0;i<n;i++) cin>>a[i];
#define coutarr(a) for (auto d:a)cout<<d<<" "; cout<<endl;
#define coutarrD(a) for (auto d:a) cout<<d.fi<<","<<d.se<<" "; cout<<endl;
#define BERKAY_TUP ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define endl '\n'
#define ld long double
#define mid (start+end)/2
#define vvi vector<vector<int>>
int t=1;
int interactive=0;
int usaco=0;
int testCase=0;
int tree[100023];
void update(int l,int r,int x){
    r++;
    while (l<100023){
        tree[l]+=x;
        l+=l&-l;
    }
    while (r<100023){
        tree[r]-=x;
        r+=r&-r;
    }
}
int query(int x){
    int ans=0;
    while (x>0){
        ans+=tree[x];
        x-=x&-x;
    }
    return ans;
}
void solve(){
    int n;
    cin>>n;
    cinarr(h,n);
    cinarr(w,n);
    vector<pii> hh;
    int z[n];
    int sm=0;
    for (int i=0;i<n;i++){
        hh.pb({h[i],i});
        sm+=w[i];
        z[i]=sm;
    }
    sort(hh.begin(),hh.end());
    int nr[n];
    int nl[n];
    stack<pii> s;
    for (int i=0;i<n;i++){
        while (!s.empty() && s.top().fi>h[i]) s.pop();
        if (s.empty()) nl[i]=-1;
        else nl[i]=s.top().se;
        s.push({h[i],i});
    }
    stack<pii> s1;
    for (int i=n-1;i>=0;i--){
        while (!s1.empty() && s1.top().fi>h[i]) s1.pop();
        if (s1.empty()) nr[i]=n;
        else nr[i]=s1.top().se;
        s1.push({h[i],i});
    }
    int ans=0;
    
    for (int i=0;i<n;i++){
        int c=hh[i].se;
        int g=query(c+1);
        if (g==h[c]) continue;
        int a=(((g+h[c])*(h[c]-g+1))/2-g)%MOD;
        int b;
        if (nl[c]==-1) b=z[nr[c]-1];
        else b=z[nr[c]-1]-z[nl[c]];
        b=((b*(b+1))/2)%MOD;
        update(nl[c]+2,nr[c],h[c]-g);
        ans=(ans+a*b)%MOD;
    }
    cout<<ans<<endl;
    
    
    
}

 
 
 
 
 
 

 
int32_t main(){
    
    //BERKAY_TUP;
    if (usaco){
        freopen("team.in", "r", stdin);
        freopen("team.out", "w", stdout);
    }
    if (!interactive){
    #ifdef Local
        freopen("in.txt", "r", stdin);
        freopen("out.txt", "w", stdout);
        //freopen("wormsort.out", "w", stdout);
    #endif
    }
    if (t==1) solve();
    else{
        cin>>t;
        while (t--){testCase++;solve();}
    }
    
        
    return 0;
}

Compilation message (stderr)

fancyfence.cpp: In function 'int32_t main()':
fancyfence.cpp:109:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  109 |         freopen("team.in", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
fancyfence.cpp:110:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  110 |         freopen("team.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• 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