Submission #485451

#	Time	Username	Problem	Language	Result	Execution time	Memory
485451		MilosMilutinovic	Vudu (COCI15_vudu)	C++14	140 / 140	304 ms	33488 KiB

vudu

#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
mt19937 mrand(random_device{}()); 
const ll mod=1000000007;
const ll mod2=998244353;
int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

const int N=1010000;
int n,p,a[N],c[N];
ll pf[N];

int query(int x) {
	int s=0;
	for (;x;x-=x&-x) s+=c[x];
	return s;
}

void modify(int x,int s) {
	for (;x<N;x+=x&-x) c[x]+=s;
}

int main() {
	scanf("%d",&n);
	rep(i,1,n+1) scanf("%d",a+i),pf[i]=pf[i-1]+a[i];
	scanf("%d",&p);
	vector<ll> v;
	/*(pf[i]-pf[j])/(i-j)>=p
	pf[i]-pf[j]>=p*i-p*j
	pf[i]-p*i>=pf[j]-p*j*/
	rep(i,0,n+1) v.pb(pf[i]-(ll)p*i);
	sort(all(v));
	v.erase(unique(all(v)),v.end());
	ll ans=0;
	rep(i,0,n+1) {
		int x=lower_bound(all(v),pf[i]-(ll)p*i)-v.begin()+1;
		ans+=query(x);
		modify(x,1);
	} 
	printf("%lld",ans);
}

Compilation message (stderr)

vudu.cpp: In function 'int main()':
vudu.cpp:38:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |  scanf("%d",&n);
      |  ~~~~~^~~~~~~~~
vudu.cpp:39:20: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |  rep(i,1,n+1) scanf("%d",a+i),pf[i]=pf[i-1]+a[i];
      |               ~~~~~^~~~~~~~~~
vudu.cpp:40:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |  scanf("%d",&p);
      |  ~~~~~^~~~~~~~~

• Subtask 1: 140 / 140