Submission #929218

#	Time	Username	Problem	Language	Result	Execution time	Memory
929218		OAleksa	Horses (IOI15_horses)	C++14	54 / 100	1563 ms	47444 KiB

horses

#include "horses.h"
#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
const int inf = 1e18 + 69;
const int N = 5e5 + 69;
int n, a[N], b[N], c[N], p[4 * N], g[4 * N], btr[4 * N];
int mul(int x, int y) {
   long long r = 1ll * x * y;
   if (r >= mod)
      r %= mod;
   return r;
}

void modify(int v, int tl, int tr, int pos, int x) {
   if (tl == tr)
      p[v] = g[v] = x;
   else {
      int mid = (tl + tr) / 2;
      if (pos <= mid)
         modify(v * 2, tl, mid, pos, x);
      else
         modify(v * 2 + 1, mid + 1, tr, pos, x);
      if (p[v * 2] == -1 || p[v * 2 + 1] == -1 || p[v * 2] > inf / p[v * 2 + 1])
         p[v] = -1;
      else {
         assert(p[v * 2] * p[v * 2 + 1] < inf);
         p[v] = p[v * 2] * p[v * 2 + 1];
      }
      g[v] = mul(g[v * 2], g[v * 2 + 1]);
   }
}

int get(int v, int tl, int tr, int l, int r) {
   if (tl > r || tr < l)
      return 1;
   else if (tl >= l && tr <= r)
      return p[v];
   else {
      int mid = (tl + tr) / 2;
      auto l1 = get(v * 2, tl, mid, l, r);
      auto r1 = get(v * 2 + 1, mid + 1, tr, l, r);
      if (l1 == -1 || r1 == -1 || l1 > inf / r1)
         return -1;
      assert(l1 * r1 < inf);
      return l1 * r1;
   }
}
int Get(int v, int tl, int tr, int l, int r) {
   if (tl > r || tr < l)
      return 1;
   else if (tl >= l && tr <= r)
      return g[v];
   else {
      int mid = (tl + tr) / 2;
      return mul(Get(v * 2, tl, mid, l, r), Get(v * 2 + 1, mid + 1, tr, l, r));
   }
}
int Better(int i, int j) {
   if (i > j)
      swap(i, j);
   int x = 1;
   for (int L = i + 1;L <= j;L++) {
      if (x > inf / a[L]) {
         x = -1;
         break;
      }
      x *= a[L];
   }
   if (x < 0 || x > inf / b[j])
      return j;
   return (b[i] > b[j] * x ? i : j);
}
int Result(int i) {
   return mul(Get(1, 1, n, 1, i), b[i]);
}
void Modify(int v, int tl, int tr, int pos, int x) {
   if (tl == tr)
      btr[v] = x;
   else {
      int mid = (tl + tr) / 2;
      if (pos <= mid)
         Modify(v * 2, tl, mid, pos, x);
      else
         Modify(v * 2 + 1, mid + 1, tr, pos, x);
      if (btr[v * 2] == -1)
         btr[v] = btr[v * 2 + 1];
      else if (btr[v * 2 + 1] == -1)
         btr[v] = btr[v * 2];
      else
         btr[v] = Better(btr[v * 2], btr[v * 2 + 1]);
   }
}

int init(int N, int X[], int Y[]) {
   n = N;
   fill(p, p + 4 * n + 10, 1);
   fill(g, g + 4 * n + 10, 1);
   fill(btr, btr + 4 * n + 10, -1);
   for (int i = 1;i <= n;i++) {
      a[i] = X[i - 1], b[i] = Y[i - 1];
      modify(1, 1, n, i, a[i]);
   }
   for (int i = 1;i <= n;i++)
      Modify(1, 1, n, i, i);
   return Result(btr[1]);
}

int updateX(int pos, int val) {
   pos++;
   a[pos] = val;
   modify(1, 1, n, pos, a[pos]);
   Modify(1, 1, n, pos, pos);
	return Result(btr[1]);
}

int updateY(int pos, int val) {
   pos++;
	b[pos] = val;
	modify(1, 1, n, pos, a[pos]);
   Modify(1, 1, n, pos, pos);
	return Result(btr[1]);
}
/*
3
2 1 3
3 4 1
1
2 1 2
*/

Compilation message (stderr)

horses.cpp:5:22: warning: overflow in conversion from 'double' to 'int' changes value from '1.0000000000000001e+18' to '2147483647' [-Woverflow]
    5 | const int inf = 1e18 + 69;
      |                 ~~~~~^~~~
horses.cpp: In function 'int mul(int, int)':
horses.cpp:12:11: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   12 |    return r;
      |           ^
horses.cpp: In function 'int init(int, int*, int*)':
horses.cpp:95:14: warning: declaration of 'N' shadows a global declaration [-Wshadow]
   95 | int init(int N, int X[], int Y[]) {
      |          ~~~~^
horses.cpp:6:11: note: shadowed declaration is here
    6 | const int N = 5e5 + 69;
      |           ^

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