Submission #1025237

#	Time	Username	Problem	Language	Result	Execution time	Memory
1025237		YassirSalama	Horses (IOI15_horses)	C++17	100 / 100	1126 ms	57424 KiB

horses

#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define all(v) v.begin(),v.end()
#define ll long long
template<typename T> 
void dbg_out(const T& t){
	cout<<t<<endl;
}
template<typename T,typename... Args>
void dbg_out(const T& t,const Args&... args){
	cout<<t<<" , ";
	dbg_out(args...);
}
#define dbg(...) cout<<"("<<#__VA_ARGS__<<"): ";dbg_out(__VA_ARGS__);
const ll mod=1e9+7;
const int maxn=5e5+1;
ll tree[4*maxn];
void update(int node,int l,int r,int ql,ll x){
	if(l==r){
		tree[node]=x;
		return;
	}
	int mid=(l+r)/2;
	if(ql<=mid)
		update(node<<1,l,mid,ql,x);
	if(ql>mid)
		update(node<<1|1,mid+1,r,ql,x);
	tree[node]=max(tree[node<<1],tree[node<<1|1]);
}
ll query(int node,int l,int r,int ql,int qr){
	if(ql>=qr) return 0LL;
	if(ql<=l&&r<=qr) return tree[node];
	int mid=(l+r)/2;
	ll ans=0;
	if(ql<=mid) ans=max(ans,query(node<<1,l,mid,ql,qr));
	if(qr>mid) ans=max(ans,query(node<<1|1,mid+1,r,ql,qr));
	return ans;
}
int n;
vector<ll> x;
vector<ll> y;
set<int> s;
ll ymx=1e9;
ll pref=1;
ll binpow(int a,int b){
	ll ans=1;
	while(b){
		if(b&1) ans=(ans%mod*a%mod)%mod;
		b>>=1;
		a=(a%mod*a%mod)%mod;
	}
	return ans;
}
ll invmod(int a){
	return binpow(a,mod-2);
}
ll solve(){
	ll suff=1;
	ll p=pref;
	int last=n;
    for(auto i:s){
    	i=-i;
    	suff=max(suff,1LL*query(1,0,n,i,last));
    	last=i;
    	if(suff>=ymx){
    		suff%=mod;
    		return (p%mod*suff%mod)%mod;
    	}
    	suff*=x[i];
    	p=(p%mod*invmod(x[i])%mod)%mod;
    }
    return max(suff*p,1LL*query(1,0,n,0,last))%mod;
}
int init(int N, int X[], int Y[]) {
	n=N;
	x.resize(n,0);
	y.resize(n,0);
	for(int i=0;i<n;i++){
		x[i]=X[i];
		if(x[i]>1){
			s.insert(-i);
		}
		pref=pref*x[i]%mod;
	}
	for(int i=0;i<n;i++){
		y[i]=Y[i];
		update(1,0,n,i,y[i]);
	}
	return (int)((ll)solve()%mod);
}
 
int updateX(int pos, int val) {	
	pref=(pref%mod*invmod(x[pos])%mod)%mod;
	if(x[pos]>1){
		s.erase(-pos);
	}
	x[pos]=val;
	x[pos]%=mod;
	if(x[pos]>1) s.insert(-pos);
	pref=(pref%mod*x[pos]%mod)%mod;
	return solve()%mod;
}
 
int updateY(int pos, int val) {
	y[pos]=val;
	y[pos]%=mod;
	update(1,0,n,pos,val);
	return solve()%mod;
}
 
 
#ifdef IOI
 
 
static char _buffer[1024];
static int _currentChar = 0;
static int _charsNumber = 0;
static FILE *_inputFile, *_outputFile;
 
static inline int _read() {
    if (_charsNumber < 0) {
        exit(1);
    }
    if (!_charsNumber || _currentChar == _charsNumber) {
        _charsNumber = (int)fread(_buffer, sizeof(_buffer[0]), sizeof(_buffer), _inputFile);
        _currentChar = 0;
    }
    if (_charsNumber <= 0) {
        return -1;
    }
    return _buffer[_currentChar++];
}
 
static inline int _readInt() {
    int c, x, s;
    c = _read();
    while (c <= 32) c = _read();
    x = 0;
    s = 1;
    if (c == '-') {
        s = -1;
        c = _read();
    }
    while (c > 32) {
        x *= 10;
        x += c - '0';
        c = _read();
    }
    if (s < 0) x = -x;
    return x;
}
 
 
int main() {
	// _inputFile = fopen("horses.in", "rb");
	// _outputFile = fopen("horses.out", "w");
	
	int N; 
	cin>>N;
 
	int *X = (int*)malloc(sizeof(int)*(unsigned int)N);
	int *Y = (int*)malloc(sizeof(int)*(unsigned int)N);
 
	for (int i = 0; i < N; i++) {
		cin>>X[i];
	}
 
	for (int i = 0; i < N; i++) {
		cin>>Y[i];
	}	
	cout<<init(N,X,Y)<<endl;
 
 
	int M; 
	// M = _readInt();
	cin>>M;
 
	for (int i = 0; i < M; i++) {
		int type; 
		int pos; 
		int val; 
		cin>>type>>pos>>val;
		if (type == 1) {
			cout<<updateX(pos,val)<<endl;
			// fprintf(_outputFile,"%d\n",updateX(pos,val));
		} else if (type == 2) {
			cout<<updateY(pos,val)<<endl;
			// fprintf(_outputFile,"%d\n",updateY(pos,val));
		}
	}
 
	return 0;
}
 
#endif 

Compilation message (stderr)

horses.cpp: In function 'long long int binpow(int, int)':
horses.cpp:52:18: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   52 |   a=(a%mod*a%mod)%mod;
      |     ~~~~~~~~~~~~~^~~~
horses.cpp: In function 'long long int solve()':
horses.cpp:72:26: warning: conversion from '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'} to 'int' may change value [-Wconversion]
   72 |      p=(p%mod*invmod(x[i])%mod)%mod;
      |                          ^
horses.cpp: In function 'int updateX(int, int)':
horses.cpp:95:30: warning: conversion from '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'} to 'int' may change value [-Wconversion]
   95 |  pref=(pref%mod*invmod(x[pos])%mod)%mod;
      |                              ^
horses.cpp:103:16: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
  103 |  return solve()%mod;
      |         ~~~~~~~^~~~
horses.cpp: In function 'int updateY(int, int)':
horses.cpp:110:16: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
  110 |  return solve()%mod;
      |         ~~~~~~~^~~~

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