Submission #698604

#	Time	Username	Problem	Language	Result	Execution time	Memory
698604		vjudge1	Xylophone (JOI18_xylophone)	C++17	100 / 100	121 ms	336 KiB

xylophone

#include "xylophone.h"
#include <bits/stdc++.h>
using namespace std;
static int A[5005];

void solve(int N) {
	int nxt[N], tri[N-1];
	for(int i = 1; i < N; ++i) {
		nxt[i] = query(i, i + 1);
	}
	for(int i = 1; i < N - 1; ++i) {
		tri[i] = query(i, i + 2);
	}
	bool turn[N + 5];
	for(int i = 2; i < N; ++i) {
		turn[i] = tri[i - 1] != nxt[i - 1] + nxt[i];
	}
	// assume a[1] == 1 and go up
	// shift everything later on
	// if pos 1 > pos N then make everything A[i] = N - A[i]
	A[1] = 1;
	bool up = 1;
	for(int i = 2; i <= N; ++i) {
		if(up)
			A[i] = A[i - 1] + nxt[i - 1];
		else
			A[i] = A[i - 1] - nxt[i - 1];
		if(i != N)
			up ^= turn[i];
	}
	int min_elem = 1e9, idx;
	for(int i = 1; i <= N; ++i) {
		if(A[i] < min_elem)
			idx = i, min_elem = A[i];
	}
	for(int i = 1; i <= N; ++i)
		A[i] += 1 - min_elem;
	int onepos, npos;
	for(int i = 1; i <= N; ++i) {
		if(A[i] == 1)
			onepos = i;
		if(A[i] == N)
			npos = i;
	}	
	if(onepos > npos) {
		for(int i = 1; i <= N; ++i)
			A[i] = N + 1 - A[i];
	}
	//for(int i = 1; i <= N; ++i)
	//	cout << A[i] << " ";
	//cout << endl;
	for(int i = 1; i <= N; ++i)
		answer(i, A[i]);
}

Compilation message (stderr)

xylophone.cpp: In function 'void solve(int)':
xylophone.cpp:31:22: warning: variable 'idx' set but not used [-Wunused-but-set-variable]
   31 |  int min_elem = 1e9, idx;
      |                      ^~~
xylophone.cpp:45:2: warning: 'onepos' may be used uninitialized in this function [-Wmaybe-uninitialized]
   45 |  if(onepos > npos) {
      |  ^~
xylophone.cpp:45:2: warning: 'npos' may be used uninitialized in this function [-Wmaybe-uninitialized]

• Subtask 1: 11 / 11
• Subtask 2: 36 / 36
• Subtask 3: 53 / 53