Submission #996111

#	Time	Username	Problem	Language	Result	Execution time	Memory
996111		anHiep	Xylophone (JOI18_xylophone)	C++17	100 / 100	232 ms	97624 KiB

xylophone

#include "xylophone.h"
#include<bits/stdc++.h>

using namespace std;

static int a[5005];
static int d[5005][5005]; 

void solve(int n) {
	int dis = query(1, 2);
    for(int i=3; i<=n; i++) {
        d[i - 2][i] = query(i - 2, i);
        d[i - 1][i] = query(i - 1, i);
    }
    for(int i=1; i<=n; i++) {
        a[1] = i;
        for(int k=-1; k<=1; k+=2) {
            a[2] = a[1] + k*dis;
            for(int j=3; j<=n; j++) {
                int cal = max(a[j - 1], a[j - 2]) - min(a[j - 1], a[j - 2]);
                if(d[j - 2][j] == cal) {
                    if(a[j - 1] > a[j - 2]) a[j] = a[j - 1] - d[j - 1][j];
                    else a[j] = a[j - 1] + d[j - 1][j];
                }
                else {
                    if(a[j - 1] + d[j - 1][j] - min(a[j - 2], a[j - 1]) == d[j - 2][j]) a[j] = a[j - 1] + d[j - 1][j];
                    if(max(a[j - 2], a[j - 1]) - (a[j - 1] - d[j - 1][j]) == d[j - 2][j]) a[j] = a[j - 1] - d[j - 1][j];
                }
            }
            int mi = 1e9, mx = -1e9;
            long long sum = 0;
            for(int j=1; j<=n; j++) {
                mi = min(mi, a[j]);
                mx = max(mx, a[j]);
                sum += a[j];
            }
            if(mi == 1 && mx == n && sum == 1LL*n*(n + 1)/2) {
                int p1, pn;
                for(int j=1; j<=n; j++) {
                    if(a[j] == 1) p1 = j;
                    if(a[j] == n) pn = j;
                } 
                if(p1 < pn) {
                    for(int j=1; j<=n; j++) answer(j, a[j]);
                    return;
                }
            }
        }
    }
}

Compilation message (stderr)

xylophone.cpp: In function 'void solve(int)':
xylophone.cpp:43:17: warning: 'pn' may be used uninitialized in this function [-Wmaybe-uninitialized]
   43 |                 if(p1 < pn) {
      |                 ^~
xylophone.cpp:43:17: warning: 'p1' may be used uninitialized in this function [-Wmaybe-uninitialized]

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