Submission #470693

#	Time	Username	Problem	Language	Result	Execution time	Memory
470693		Millad	Xylophone (JOI18_xylophone)	C++14	100 / 100	127 ms	576 KiB

xylophone

// In the name of god
#include "xylophone.h"
#include <bits/stdc++.h>

#define F first
#define S second
#define pb push_back
#define debug(x) cerr << #x << " : " << x << '\n'

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> pll;

const ll maxn = 5e3 + 5;

ll b1[maxn], b2[maxn], d1[maxn], d2[maxn];
bool flag1[maxn], flag2[maxn];
void build_b1(int n){
	flag1[1] = 1;
        for(ll i = 1; i < n; i ++){     
                if(flag1[i])b1[i + 1] = b1[i] + d1[i];
                else b1[i + 1] = b1[i] - d1[i];
                if(i < n - 1){
                        if(d2[i] == d1[i] + d1[i + 1])flag1[i + 1] = flag1[i];
                        else flag1[i + 1] = !flag1[i];
                }
        }
	ll mn = (n * 10);
	for(ll i = 1; i <= n; i ++)mn = min(mn, b1[i]);
	for(ll i = 1; i <= n; i ++)b1[i] += (1 - mn);
}
void build_b2(int n){
        flag2[1] = 0;
        for(ll i = 1; i < n; i ++){
                if(flag2[i])b2[i + 1] = b2[i] + d1[i];
                else b2[i + 1] = b2[i] - d1[i];
                if(i < n - 1){
                        if(d2[i] == d1[i] + d1[i + 1])flag2[i + 1] = flag2[i];
                        else flag2[i + 1] = !flag2[i];
                }
        }
        ll mn = (n * 10);
        for(ll i = 1; i <= n; i ++)mn = min(mn, b2[i]);
        for(ll i = 1; i <= n; i ++)b2[i] += (1 - mn);
}
void solve(int n){
	for(ll i = 1; i < n; i ++)d1[i] = query(i, i + 1);
	for(ll i = 1; i < n - 1; i ++)d2[i] = query(i, i + 2);
	build_b1(n); build_b2(n);
	ll p1, pn;
	for(ll i = 1; i <= n; i ++){
		if(b1[i] == 1)p1 = i;
		if(b1[i] == n)pn = i;
	}
	if(p1 > pn)
		for(ll i = 1; i <= n; i ++)answer(i, b2[i]);
	else
		for(ll i = 1; i <= n; i ++)answer(i, b1[i]);
}

Compilation message (stderr)

xylophone.cpp: In function 'void solve(int)':
xylophone.cpp:56:2: warning: 'pn' may be used uninitialized in this function [-Wmaybe-uninitialized]
   56 |  if(p1 > pn)
      |  ^~
xylophone.cpp:56:2: warning: 'p1' may be used uninitialized in this function [-Wmaybe-uninitialized]

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