Submission #62300

#	Time	Username	Problem	Language	Result	Execution time	Memory
62300		Tenuun	Horses (IOI15_horses)	C++17	17 / 100	585 ms	46916 KiB

horses

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

using namespace std;

int n, tr[2000000], id[500001];
ll bit[500001];
ll now=1;
vector<int>x, y;
set<int>a;

void update(int ind, int val){
	if(ind==0) bit[0]=(bit[0]*val)%mod, ind++;
	while(ind<=500000){
		bit[ind]*=val;
		bit[ind]%=mod;
		ind+=ind&-ind;
	}
}

ll get(int ind){
	ll ans=bit[0];
	while(ind){
		ans*=bit[ind];
		ans%=mod;
		ind-=ind&-ind;
	}
	return ans;
}

void pre(){
	memset(bit, 1, sizeof bit);
	int last=-1;
	a.insert(-1);
	a.insert(0);
	for(int i=0; i<n; i++){
		if(x[i]>1){
			a.insert(i);
			update(i, x[i]);
		}
	}
}

void build(int ind, int l, int r){
	if(l==r){
		tr[ind]=y[l];
		id[l]=ind;
		return;
	}
	build(ind*2, l, (l+r)/2);
	build(ind*2+1, (l+r)/2+1, r);
	tr[ind]=max(tr[ind*2], tr[ind*2+1]);
}

void upd(int ind){
	if(ind==0) return;
	tr[ind]=max(tr[ind*2], tr[ind*2+1]);
	upd(ind/2);
}

ll rmq(int ind, int l, int r, int L, int R){
	if(l==L && r==R) return tr[ind];
	int m=(l+r)/2;
	if(R<=m) return rmq(ind*2, l, m, L, R);
	else if(L>m) return rmq(ind*2+1, m+1, r, L, R);
	else{
		return max(rmq(ind*2, l, m, L, m), rmq(ind*2+1, m+1, r, m+1, R));
	}
}

ll find(){
	ll ans=1;
	ll now=rmq(1, 0, n-1, *prev(a.end()), n-1);
	set<int>::iterator it;
	for(it=prev(a.end()); it!=a.begin() && now<mod; it--){
		if(now*x[*it]>mod) break;
		now*=x[*it];
	}
	ans=now;
	now/=rmq(1, 0, n-1, *prev(a.end()), n-1);
	for(set<int>::iterator tmp=prev((prev(a.end()))); tmp!=prev(it) && tmp!=a.begin(); tmp--){
		now/=x[*next(tmp)];
		ans=max(ans, now*rmq(1, 0, n-1, *tmp, *next(tmp)-1));
	}
	ans%=mod;
	if(it!=a.begin()) ans*=get(*it);
	ans%=mod;
	/*for(; it!=a.begin(); it--){
		ans*=x[*it];
		ans%=mod;
	}*/
	return ans;
}

int init(int N, int X[], int Y[]) {
	n=N;
	for(int i=0; i<n; i++) {x.push_back(X[i]); y.push_back(Y[i]);}
	pre();
	build(1, 0, n-1);
	return find();
}

ll pw(ll o, ll p){
	if(p==0) return 1;
	ll ans=pw(o, p/2);
	ans*=ans;
	ans%=mod;
	if(p%2) ans*=o;
	ans%=mod;
	return ans;
}

int updateX(int pos, int val){
	if(x[pos]==1 && val==1) return find();
	if(x[pos]>1 && val>1){
		update(pos, pw(x[pos], mod-2));
		update(pos, val);
		x[pos]=val;
		///now/x[pos]*val;
		return find();
	}
	else if(x[pos]==1){
		a.insert(pos);
		update(pos, val);
		x[pos]=val;
	}
	else{
		a.erase(a.find(pos));
		update(pos, pw(x[pos], mod-2));
		x[pos]=1;
	}
	return find();
}

int updateY(int pos, int val){
	tr[id[pos]]=val;
	upd(id[pos]/2);
	return find();
}

Compilation message (stderr)

horses.cpp: In function 'void pre()':
horses.cpp:34:6: warning: unused variable 'last' [-Wunused-variable]
  int last=-1;
      ^~~~
horses.cpp: In function 'long long int find()':
horses.cpp:74:5: warning: declaration of 'now' shadows a global declaration [-Wshadow]
  ll now=rmq(1, 0, n-1, *prev(a.end()), n-1);
     ^~~
horses.cpp:9:4: note: shadowed declaration is here
 ll now=1;
    ^~~
horses.cpp: In function 'int init(int, int*, int*)':
horses.cpp:101:13: warning: conversion to 'int' from 'long long int' may alter its value [-Wconversion]
  return find();
         ~~~~^~
horses.cpp: In function 'int updateX(int, int)':
horses.cpp:115:37: warning: conversion to 'int' from 'long long int' may alter its value [-Wconversion]
  if(x[pos]==1 && val==1) return find();
                                 ~~~~^~
horses.cpp:117:17: warning: conversion to 'int' from 'long long int' may alter its value [-Wconversion]
   update(pos, pw(x[pos], mod-2));
               ~~^~~~~~~~~~~~~~~
horses.cpp:121:14: warning: conversion to 'int' from 'long long int' may alter its value [-Wconversion]
   return find();
          ~~~~^~
horses.cpp:130:17: warning: conversion to 'int' from 'long long int' may alter its value [-Wconversion]
   update(pos, pw(x[pos], mod-2));
               ~~^~~~~~~~~~~~~~~
horses.cpp:133:13: warning: conversion to 'int' from 'long long int' may alter its value [-Wconversion]
  return find();
         ~~~~^~
horses.cpp: In function 'int updateY(int, int)':
horses.cpp:139:13: warning: conversion to 'int' from 'long long int' may alter its value [-Wconversion]
  return find();
         ~~~~^~

• Subtask 1: 17 / 17
• Subtask 2: 0 / 17
• Subtask 3: 0 / 20
• Subtask 4: 0 / 23
• Subtask 5: 0 / 23