Submission #838353

#	Time	Username	Problem	Language	Result	Execution time	Memory
838353		AbdelmagedNour	Horses (IOI15_horses)	C++17	100 / 100	521 ms	51208 KiB

horses

#include <bits/stdc++.h>
using namespace std;
//#include "grader.cpp"
#include "horses.h"
const int mod=(1e9)+7,MAXN=500005;
int add(int a,int b){
	a+=b;
    if(a>=mod)a-=mod;
    return a;
}
int sub(int a,int b){
    a-=b;
    if(a<0)a+=mod;
    return a;
}
int mul(int a,int b){
	return(a*1LL*b)%mod;
}
int power(int x,int n){
    int res=1;
    while(n){
        if(n&1)res=mul(res,x);
        x=mul(x,x);
        n>>=1;
    }
    return res;
}
int inv(int a){
	return power(a,mod-2);
}
int divide(int a,int b){
	return mul(a,inv(b));
}
int x[MAXN],y[MAXN],n;
set<int>not_one;
int bit[MAXN],tree[1<<20];
void upd(int i,int val){
    for(;i<=n;i+=i&-i)bit[i]=mul(bit[i],val);
}
int qry(int i){
	int res=1;
    for(;i>=1;i-=i&-i)res=mul(res,bit[i]);
	return res;
}
void update(int l,int r,int p,int idx,int val){
    if(l==r){
        tree[p]=val;
        return;
    }
    int md=(l+r)>>1;
    if(md>=idx)update(l,md,p*2+1,idx,val);
    else update(md+1,r,p*2+2,idx,val);
    tree[p]=max(tree[p*2+1],tree[p*2+2]);
}
int query(int l,int r,int p,int l_q,int r_q){
    if(l>r_q||r<l_q)return 0;
    if(l>=l_q&&r<=r_q)return tree[p];
    int md=(l+r)>>1;
    return max(query(l,md,p*2+1,l_q,r_q),query(md+1,r,p*2+2,l_q,r_q));
}
int solve(){
	long long cur_factor=1,all_factor=1;
	int last=n+1;
	long long ans=0,best=0;
	for(auto it=not_one.rbegin();it!=not_one.rend();it++){
		int cur_pos=*it;
	    int cur_y=query(1,n,0,cur_pos,last-1);
		if(cur_y>best*cur_factor) {
			best=cur_y;
			ans=mul(qry(cur_pos),cur_y);
			cur_factor=1;
		}
		cur_factor*=x[cur_pos];
		all_factor*=x[cur_pos];
		if(all_factor>mod)break;
		last=cur_pos;
	}
	return ans;
}
int init(int N, int X[], int Y[]) {
	n=N;
	x[0]=y[0]=1;
	for(int i=1;i<=n;i++)x[i]=X[i-1],y[i]=Y[i-1];
	for(int i=0;i<=n;i++)bit[i]=1;
	for(int i=1;i<=n;i++){
		upd(i,x[i]);
		update(1,n,0,i,y[i]);
	}
	for(int i=1;i<=n;i++){
		if(x[i]>1)not_one.insert(i);
	}
	not_one.insert(1);
	return solve();
}
int updateX(int pos,int val){	
    pos++;
    upd(pos,divide(val,x[pos]));
	if(x[pos]>1&&pos>1)not_one.erase(pos);
    x[pos]=val;
    if(x[pos]>1)not_one.insert(pos);
    return solve();
}

int updateY(int pos,int val){
    pos++;
    y[pos]=val;
    update(1,n,0,pos,val);
	return solve();
}

Compilation message (stderr)

horses.cpp: In function 'int mul(int, int)':
horses.cpp:17:17: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   17 |  return(a*1LL*b)%mod;
      |        ~~~~~~~~~^~~~
horses.cpp: In function 'int solve()':
horses.cpp:78:9: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   78 |  return ans;
      |         ^~~

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