Submission #906581

#	Time	Username	Problem	Language	Result	Execution time	Memory
906581		Ludissey	Fancy Fence (CEOI20_fancyfence)	C++14	100 / 100	31 ms	6004 KiB

fancyfence

#include <bits/stdc++.h>
using namespace std;
#define int long long
 
int n,m;
int mod=1e9+7;
int MOD(int x) {
    return (x+mod)%mod;
}
int clc(int x, int y) {
    x=MOD(x);
    y=MOD(y); 
    return (((((x*(x+1)))/(long long)2)%mod)*((((y*(y+1)))/(long long)2)%mod))%mod; //non cest bon 
}
signed main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);
    cin >> n;
    vector<int> h(n+1);
    vector<int> w(n+1);
    int totalw=0;
    for (int i = 1; i <= n; i++) cin>>h[i];
    for (int i = 1; i <= n; i++) cin >> w[i];
    h[0]=0;
    stack<pair<int,int>> stck;
    int outp=0;
    stck.push({h[1],w[1]});
    for (int i = 2; i <= n; i++)
    {
        int hght=stck.top().first;
        int wdht=stck.top().second;
        stck.pop();
        if(hght==h[i]) {
            wdht+=w[i];
            stck.push({hght, wdht});
        }
        else if(hght<h[i]){
            stck.push({hght, wdht});
            stck.push({h[i], w[i]});
        }else{
            bool b=true;
            vector<pair<int,int>> sb4;
            int copyw=w[i];
            while(hght>h[i]){
                w[i]=(w[i]+wdht)%mod;
                sb4.push_back({wdht,hght});
                if(!b) stck.pop();
                if(stck.empty()) break;
                b=false;
                hght=stck.top().first;
                wdht=stck.top().second;
            }
            int totw=w[i]-copyw;
            int last=0;
            for (int j = sb4.size()-1; j >= 0; j--)
            {
                int height=sb4[j].second, width=sb4[j].first;
                int side1=clc(totw,height)-clc(totw,last);
                last=height;
                side1=MOD(side1); // 
                outp=MOD(outp+side1); //jai pas compris
                totw-=width;
            }
            int min=clc(MOD(w[i]-copyw),h[i]);
            outp=MOD(outp-min);
            stck.push({h[i], w[i]});
        }
    }
    h.clear();
    w.clear();
    int newN=stck.size();
    h.resize(newN);
    w.resize(newN);
    totalw=0;
    for (int i = newN; i > 0; i--)
    {
        h[i]=stck.top().first;
        w[i]=stck.top().second;
        totalw=(totalw+w[i])%mod;
        stck.pop();
    }
    h[0]=0;
    for (int i = 1; i <= newN; i++)
    {
        int side1=clc(totalw,h[i])-clc(totalw,h[i-1]);
        side1=MOD(side1); // 
        outp=MOD(outp+side1); //jai pas compris
        totalw-=w[i];
    }
    cout << outp << "\n";
    return 0;
}

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