Submission #68311

#	TimeUTC-0	Username	Problem	Language	Result	Execution time	Memory
68311	2018-08-16 15:34:01	thebes	Watching (JOI13_watching)	C++14	100 / 100	513 ms	16668 KiB

watching

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
#include <bits/stdc++.h>
using namespace std;
const int MN = 2002;
int pos[MN], N, P, Q, i, lo, hi, l, r, k, nxt[MN], nxt2[MN], dp[MN][MN];
int solve(int n,int rem){
  if(n == N+1) return 0;
  else if(dp[n][rem]!=-1) return dp[n][rem];
  if(rem) dp[n][rem]=min(solve(nxt[n],rem-1),solve(nxt2[n],rem)+1);
  else dp[n][rem]=solve(nxt2[n],rem)+1;
  return dp[n][rem];
}
bool check(int w){
  for(l=r=k=1;l<=N;l++){
    while(r<=N&&pos[r]-w+1<=pos[l]) r++;
    while(k<=N&&pos[k]-2*w+1<=pos[l]) k++;
    nxt[l] = r; nxt2[l] = k;
  }
  memset(dp, -1, sizeof(dp));
  return solve(1,P)<=Q;
}
int main(){
  for(scanf("%d%d%d",&N,&P,&Q),i=1;i<=N;i++)
    scanf("%d",&pos[i]);
  P = min(P, N);
  sort(pos+1,pos+N+1);
  lo = 1, hi = 1e9+7;
  while(lo < hi){
    int m = lo+hi>>1;
    if(check(m)) hi=m;
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Compilation message (stderr)

watching.cpp: In function 'int main()':
watching.cpp:29:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   int m = lo+hi>>1;
           ~~^~~
watching.cpp:23:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(scanf("%d%d%d",&N,&P,&Q),i=1;i<=N;i++)
      ~~~~~~~~~~~~~~~~~~~~~~~~^~~~
watching.cpp:24:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&pos[i]);
   ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50