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Submission #27785

# Submission time Handle Problem Language Result Execution time Memory
27785 2017-07-14T06:00:50 Z 서규호(#1160) Sparklers (JOI17_sparklers) C++14
30 / 100
 2000 ms 2800 KB 
#include <bits/stdc++.h>

#define lld long long
#define pii pair<int,int>
#define pll pair<lld,lld>
#define pb push_back
#define next nextt
#define left leftt
#define right rightt
#define Inf 1000000000
#define Linf 1000000000000000000LL
#define Mod 1000000007

using namespace std;

int N,M,ans; lld T;
lld a[100002];


bool flag; lld memo;
void dfs(lld l,lld r,lld s,lld e){
	lld X = memo;
	if(r-l == N-1 || flag){
		flag = true;
		return;
	}
	lld cnt = r-l+1;
	if(r != N && max(s-X,a[r+1]-X*cnt) <= min(e+X,a[r+1]+X*cnt)){
		dfs(l,r+1,max(s-X,a[r+1]-X*cnt),min(e+X,a[r+1]+X*cnt));
	}
	if(l != 1 && max(s-X,a[l-1]-X*cnt) <= min(e+X,a[l-1]+X*cnt)){
		dfs(l-1,r,max(s-X,a[l-1]-X*cnt),min(e+X,a[l-1]+X*cnt));
	}
}

bool can(lld X){
	X *= T; X %= Mod;
	int l,r; lld cnt;
	lld s,e;

	l = r = M; cnt = 1;
	s = e = a[M];
	memo = X;

	/*while(r-l != N-1){
		if(r != N && max(s-X,a[r+1]-X*cnt) <= min(e+X,a[r+1]+X*cnt)){
			s = max(s-X,a[r+1]-X*cnt);
			e = min(e+X,a[r+1]+X*cnt);
			r++;
		}else if(l != 1 && max(s-X,a[l-1]-X*cnt) <= min(e+X,a[l-1]+X*cnt)){
			s = max(s-X,a[l-1]-X*cnt);
			e = min(e+X,a[l-1]+X*cnt);
			l--;
		}else return false;
		s = max((lld)0,s); e = min(e,(lld)Mod);
		cnt++;
	}*/
	flag = false;
	dfs(l,r,s,e);

	return flag;
}

int main(){
	scanf("%d %d %lld",&N,&M,&T);
	for(int i=1; i<=N; i++){
		scanf("%lld",&a[i]);
	}
	int l,r;
	l = 0; r = a[N];
	while(l <= r){
		int m = (l+r)/2;
		if(can(m)){
			ans = m;
			r = m-1;
		}else l = m+1;
	}
	printf("%d\n",ans);

	return 0;
}

Compilation message

sparklers.cpp: In function 'bool can(long long int)':
sparklers.cpp:38:15: warning: variable 'cnt' set but not used [-Wunused-but-set-variable]
  int l,r; lld cnt;
               ^
sparklers.cpp: In function 'int main()':
sparklers.cpp:65:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d %lld",&N,&M,&T);
                              ^
sparklers.cpp:67:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld",&a[i]);
                      ^

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2800 KB Output is correct
2 Correct 0 ms 2800 KB Output is correct
3 Correct 0 ms 2800 KB Output is correct
4 Correct 0 ms 2800 KB Output is correct
5 Correct 0 ms 2800 KB Output is correct
6 Correct 0 ms 2800 KB Output is correct
7 Correct 0 ms 2800 KB Output is correct
8 Correct 0 ms 2800 KB Output is correct
9 Correct 0 ms 2800 KB Output is correct
10 Correct 0 ms 2800 KB Output is correct
11 Correct 0 ms 2800 KB Output is correct
12 Correct 0 ms 2800 KB Output is correct
13 Correct 0 ms 2800 KB Output is correct
14 Correct 0 ms 2800 KB Output is correct
15 Correct 0 ms 2800 KB Output is correct
16 Correct 0 ms 2800 KB Output is correct
17 Correct 0 ms 2800 KB Output is correct
18 Correct 0 ms 2800 KB Output is correct
19 Correct 0 ms 2800 KB Output is correct
20 Correct 0 ms 2800 KB Output is correct
21 Correct 0 ms 2800 KB Output is correct

Subtask #2
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2800 KB Output is correct
2 Correct 0 ms 2800 KB Output is correct
3 Correct 0 ms 2800 KB Output is correct
4 Correct 0 ms 2800 KB Output is correct
5 Correct 0 ms 2800 KB Output is correct
6 Correct 0 ms 2800 KB Output is correct
7 Correct 0 ms 2800 KB Output is correct
8 Correct 0 ms 2800 KB Output is correct
9 Correct 0 ms 2800 KB Output is correct
10 Correct 0 ms 2800 KB Output is correct
11 Correct 0 ms 2800 KB Output is correct
12 Correct 0 ms 2800 KB Output is correct
13 Correct 0 ms 2800 KB Output is correct
14 Correct 0 ms 2800 KB Output is correct
15 Correct 0 ms 2800 KB Output is correct
16 Correct 0 ms 2800 KB Output is correct
17 Correct 0 ms 2800 KB Output is correct
18 Correct 0 ms 2800 KB Output is correct
19 Correct 0 ms 2800 KB Output is correct
20 Correct 0 ms 2800 KB Output is correct
21 Correct 0 ms 2800 KB Output is correct
22 Correct 0 ms 2800 KB Output is correct
23 Execution timed out 2000 ms 2800 KB Execution timed out
24 Halted 0 ms 0 KB -

Subtask #3
0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2800 KB Output is correct
2 Correct 0 ms 2800 KB Output is correct
3 Correct 0 ms 2800 KB Output is correct
4 Correct 0 ms 2800 KB Output is correct
5 Correct 0 ms 2800 KB Output is correct
6 Correct 0 ms 2800 KB Output is correct
7 Correct 0 ms 2800 KB Output is correct
8 Correct 0 ms 2800 KB Output is correct
9 Correct 0 ms 2800 KB Output is correct
10 Correct 0 ms 2800 KB Output is correct
11 Correct 0 ms 2800 KB Output is correct
12 Correct 0 ms 2800 KB Output is correct
13 Correct 0 ms 2800 KB Output is correct
14 Correct 0 ms 2800 KB Output is correct
15 Correct 0 ms 2800 KB Output is correct
16 Correct 0 ms 2800 KB Output is correct
17 Correct 0 ms 2800 KB Output is correct
18 Correct 0 ms 2800 KB Output is correct
19 Correct 0 ms 2800 KB Output is correct
20 Correct 0 ms 2800 KB Output is correct
21 Correct 0 ms 2800 KB Output is correct
22 Correct 0 ms 2800 KB Output is correct
23 Execution timed out 2000 ms 2800 KB Execution timed out
24 Halted 0 ms 0 KB -