Submission #492059

#	Time	Username	Problem	Language	Result	Execution time	Memory
492059		ValiAntonie	Fancy Fence (CEOI20_fancyfence)	C++14	73 / 100	1091 ms	4808 KiB

fancyfence

#include <bits/stdc++.h>
#define mod 1000000007

using namespace std;

stack <pair<long long,long long>> S;
int n,v[100005],i,dr[100005],st[100005],x,j,val,Max,nr,nr2;
long long suma[100001],total1,val1, val2,total2;
pair <int,int > sor[100005];


long long bin(long long  x){
	x %= mod;
    return ((x*(x+1))/2)%mod;
}
long long rectCount(long long x, long long y){
    return (bin(x)*bin(y))%mod;
}


int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin>>n;
for(i=1;i<=n;i++){
    cin>>v[i];
    if(v[i] == v[i-1])
        nr++;
    if(v[i] >= v[i-1])
        nr2++;
    sor[i].first = v[i];
    sor[i].second = i;
    dr[i] = n + 1;
}
sort(sor+1,sor+n+1);
for(i=1;i<=n;i++){
    cin>>x;
    suma[i] = suma[i-1] + x;
}
for(i=1;i<=n;i++){
    x = v[i];
    while(S.empty() == false && x<S.top().first){
        dr[S.top().second] = i;
        S.pop();
    }
    S.push({x,i});
}
while(S.empty() == false){
    S.pop();
}
for(i=n;i>=1;i--){
    x = v[i];
    while(S.empty() == false && x < S.top().first){
        st[S.top().second] = i;
        S.pop();
    }
    S.push({x,i});
}
//brut
for(i=1;i<=n;i++){
    total1 += rectCount(suma[dr[sor[i].second]-1] - suma[st[sor[i].second]],sor[i].first) % mod;
    total1 = total1 % mod;
    for(j=i-1;j>=1;j--){
        if(st[sor[j].second] <= sor[i].second && dr[sor[j].second] >= sor[i].second){
            Max = sor[j].first;
            break;
        }
    }
    total2 += rectCount(suma[dr[sor[i].second]-1] - suma[st[sor[i].second]],Max) % mod;
    total2 = total2 % mod;
}
if(total1 < total2)
    total1 += mod;
cout << total1 - total2 << endl;
    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: 0 / 27