Submission #63495

#	Time	Username	Problem	Language	Result	Execution time	Memory
63495		win11905	Xylophone (JOI18_xylophone)	C++11	100 / 100	172 ms	832 KiB

xylophone

#include "xylophone.h"
#include <bits/stdc++.h>
using namespace std;

int n, A[5005];

int getl() {
	int l = 1, r = n;
	while(l < r) {
		int m = l + r + 1>> 1;
		if(query(m, n) == n-1) l = m;
		r = m-1; 
	}
	return l;
}

int getNum(int a1, int a2, int a, int b) {
	if(a > b) {
		if(a2 - a1 == a - b) return a + a1;
		return a - a1;
	} else {
		if(a2 - a1 == b - a) return a - a1;
		return a + a1;
	}
}

void solve(int N) {
	n = N;
	A[1] = 0, A[2] = query(1, 2);
	for(int i = 3; i <= n; ++i) A[i] = getNum(query(i-1, i), query(i-2, i), A[i-1], A[i-2]);
	int mn = *min_element(A+1, A+n+1);
	int p1, pn;
	for_each(A+1, A+n+1, [&](int &x) { x = x - mn + 1; });
	for(int i = 1; i <= n; ++i) {
		if(A[i] == 1) p1 = i;
		if(A[i] == n) pn = i;
	}
	if(p1 > pn) for_each(A+1, A+n+1, [&](int &x) { x = n - x + 1; });
	for(int i = 1; i <= n; ++i) answer(i, A[i]);
}

Compilation message (stderr)

xylophone.cpp: In function 'int getl()':
xylophone.cpp:10:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   int m = l + r + 1>> 1;
           ~~~~~~^~~
xylophone.cpp: In function 'void solve(int)':
xylophone.cpp:38:2: warning: 'p1' may be used uninitialized in this function [-Wmaybe-uninitialized]
  if(p1 > pn) for_each(A+1, A+n+1, [&](int &x) { x = n - x + 1; });
  ^~
xylophone.cpp:38:2: warning: 'pn' may be used uninitialized in this function [-Wmaybe-uninitialized]

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