Submission #1279387

#TimeUsernameProblemLanguageResultExecution timeMemory
1279387swishy123Horses (IOI15_horses)C++20
17 / 100
25 ms15904 KiB
#include <stdio.h>
#include <stdlib.h>
#include <bits/stdc++.h>

#define ll long long
using namespace std;

const int def = 5e5+1;
const ll mod = 1e9+7;

ll powmod(ll a, ll b){
    if (b == 0)
        return 1;
    if (b % 2 == 0){
        ll val = powmod(a, b / 2);
        return (val * val) % mod;
    }
    else
        return (a * powmod(a, b - 1)) % mod;
}
ll inv(ll x){
    return powmod(x, mod - 2);
}

ll bit[def];
void apply(int u, ll val){
    for (int i = u; i < def; i += i & -i)
        (bit[i] *= val) %= mod; 
}
ll query(int u){
    ll res = 1;
    for (int i = u; i > 0; i -= i & -i)
        (res *= bit[i]) %= mod;
    return res;
}

ll x[def], y[def];
int n;

int get(){
    int l = n - 1;
    __int128_t crr = x[l];

    __int128_t bound = (__int128_t)1e18;
    while (l - 1 >= 0 && (crr * x[l - 1]) <= bound)
        l--;
    
    ll prefix = 1;
    for (int i = 0; i < l; i++)
        prefix = (prefix * x[i]) % mod;

    __int128_t best = 1;
    crr = 1;
    for (int i = l; i < n; i++){
        crr *= x[i];
        __int128_t val = crr * y[i];
        
        assert(crr <= 1e18);
        assert(y[i] <= 1e9);
        best = max(best, val);
    }
    best %= mod;
    ll res = (prefix * best) % mod;
    return res;
}

int init(int N, int X[], int Y[]){
    n = N;
    for (int i = 0; i < def; i++)
        bit[i] = 1;
    for (int i = 0; i < n; i++){
        x[i] = X[i];
        apply(i + 1, x[i]);
        y[i] = Y[i];
    }
    return get();
}

int updateX(int pos, int val){	
    apply(pos + 1, ((ll)inv(x[pos]) * (ll)val) % mod);
    x[pos] = val;
	return get();
}

int updateY(int pos, int val){
    y[pos] = val;
	return get();
}


// 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; N = _readInt();

// 	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++) {
// 		X[i] = _readInt();
// 	}

// 	for (int i = 0; i < N; i++) {
// 		Y[i] = _readInt();
// 	}	

// 	fprintf(_outputFile,"%d\n",init(N,X,Y));

// 	int M; M = _readInt();

// 	for (int i = 0; i < M; i++) {
// 		int type; type = _readInt();
// 		int pos; pos = _readInt();
// 		int val; val = _readInt(); 

// 		if (type == 1) {
// 			fprintf(_outputFile,"%d\n",updateX(pos,val));
// 		} else if (type == 2) {
// 			fprintf(_outputFile,"%d\n",updateY(pos,val));
// 		}
// 	}

// 	return 0;
// }
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