Submission #709630

#	Time	Username	Problem	Language	Result	Execution time	Memory
709630		Spade1	Xylophone (JOI18_xylophone)	C++14	100 / 100	74 ms	436 KiB

xylophone

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

int Ar[5050];
bool mark[5050];

void solve(int N) {
    int idx;
    int l = 1, r = N;
    while (l < r) {
        int mid = (l+r)/2;
        if (query(mid+1, N) == N-1) l = mid+1;
        else r = mid;
    }
    idx = l;
    Ar[idx] = 1;
    mark[1] = 1;

    for (int i = idx+1; i <= N; ++i) {
        int dif = query(i-1, i), cur;
        if (Ar[i-1]+dif>N || mark[Ar[i-1]+dif]) {
            cur = Ar[i-1]-dif;
        }
        else if (Ar[i-1]-dif<1 || mark[Ar[i-1]-dif]) {
            cur = Ar[i-1]+dif;
        }
        else {
            int dif2 = query(i-2, i);
            if (Ar[i-2] > Ar[i-1]+dif){
                if (Ar[i-2] - Ar[i-1] == dif2) cur = Ar[i-1]+dif;
            }
            if (Ar[i-2] < Ar[i-1]+dif) {
                if (Ar[i-1]+dif - min(Ar[i-2], Ar[i-1]) == dif2) cur = Ar[i-1]+dif;
            }
            if (Ar[i-2] > Ar[i-1]-dif){
                if (max(Ar[i-2], Ar[i-1]) - Ar[i-1]+dif == dif2) cur = Ar[i-1]-dif;
            }
            if (Ar[i-2] < Ar[i-1]-dif) {
                if (Ar[i-1] - Ar[i-2] == dif2) cur = Ar[i-1]-dif;
            }
        }
        Ar[i] = cur;
        mark[cur] = 1;
    }

    for (int i = idx-1; i >= 1; --i) {
        int dif = query(i, i+1), cur;
        if (Ar[i+1]+dif>N || mark[Ar[i+1]+dif]) {
            cur = Ar[i+1]-dif;
        }
        else if (Ar[i+1]-dif<1 || mark[Ar[i+1]-dif]) {
            cur = Ar[i+1]+dif;
        }
        else {
            int dif2 = query(i, i+2);
            if (Ar[i+2] > Ar[i+1]+dif){
                if (Ar[i+2] - Ar[i+1] == dif2) cur = Ar[i+1]+dif;
            }
            if (Ar[i+2] < Ar[i+1]+dif) {
                if (Ar[i+1]+dif - min(Ar[i+2], Ar[i+1]) == dif2) cur = Ar[i+1]+dif;
            }
            if (Ar[i+2] > Ar[i+1]-dif){
                if (max(Ar[i+2], Ar[i+1]) - Ar[i+1]+dif == dif2) cur = Ar[i+1]-dif;
            }
            if (Ar[i+2] < Ar[i+1]-dif) {
                if (Ar[i+1] - Ar[i+2] == dif2) cur = Ar[i+1]-dif;
            }
        }
        Ar[i] = cur;
        mark[cur] = 1;
    }

    for (int i = 1; i <= N; ++i) {
        answer(i, Ar[i]);
    }
}

Compilation message (stderr)

xylophone.cpp: In function 'void solve(int)':
xylophone.cpp:71:15: warning: 'cur' may be used uninitialized in this function [-Wmaybe-uninitialized]
   71 |         Ar[i] = cur;
      |         ~~~~~~^~~~~
xylophone.cpp:44:15: warning: 'cur' may be used uninitialized in this function [-Wmaybe-uninitialized]
   44 |         Ar[i] = cur;
      |         ~~~~~~^~~~~

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