Submission #544363

#	Time	Username	Problem	Language	Result	Execution time	Memory
544363		ValiAntonie	Fancy Fence (CEOI20_fancyfence)	C++17	100 / 100	42 ms	4272 KiB

fancyfence

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

using namespace std;

stack <pair<int,int>> S;
int n,v[100005],i,dr[100005],st[100005],x,j,val,Max,st2[100005],dr2[100005];
long long suma[100001],total1,val1, val2,total2,nr;
pair <int,int > sor[100005];


long long bin(long long  x){
    if(x > mod){
	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);
scanf("%d", &n);
for(i=1;i<=n;i++){
    scanf("%d", &v[i]);
    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++){
    scanf("%d", &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});
}

while(S.empty() == false){
    S.pop();
}
for(i=n;i>=1;i--){
    x = v[i];
    while(S.empty() == false && x<=S.top().first){
        st2[S.top().second] = i;
        S.pop();
    }
    S.push({x,i});
}
for(i=1;i<=n;i++){
    total1 = (total1 + rectCount(suma[dr[sor[i].second]-1] - suma[st[sor[i].second]],sor[i].first));
    if(total1 > mod){
        total1 -= mod;
    }
    Max = max(v[st2[sor[i].second]],v[dr[sor[i].second]]);
    total2 = (total2 + rectCount(suma[dr[sor[i].second]-1] - suma[st[sor[i].second]],Max)) % mod;
}
if(total1 < total2)
    total1 += mod;
cout << total1 - total2;
    return 0;
}

Compilation message (stderr)

fancyfence.cpp: In function 'int main()':
fancyfence.cpp:27:6: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 | scanf("%d", &n);
      | ~~~~~^~~~~~~~~~
fancyfence.cpp:29:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |     scanf("%d", &v[i]);
      |     ~~~~~^~~~~~~~~~~~~
fancyfence.cpp:36:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |     scanf("%d", &x);
      |     ~~~~~^~~~~~~~~~

• 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