Submission #951511

#	Time	Username	Problem	Language	Result	Execution time	Memory
951511		kilkuwu	Xylophone (JOI18_xylophone)	C++17	100 / 100	48 ms	744 KiB

xylophone

#include <bits/stdc++.h>

#ifndef LOCAL
#include "xylophone.h"
#else 
void solve(int N);
int query(int s, int t);
void answer(int i, int a);

static const int __N_MAX = 5000;
static const int __Q_MAX = 10000;
static int __N;
static int __A[__N_MAX];
static bool __used[__N_MAX];
static int __query_c;
static int __answer_c;

int query(int s, int t) {
	if(__query_c >= __Q_MAX) {
		printf("Wrong Answer\n");
		exit(0);
	}
	__query_c++;
	if(!(1 <= s && s <= t && t <= __N)) {
		printf("Wrong Answer\n");
		exit(0);
	}
	int mx = 0, mn = __N + 1;
	for(int i = s - 1; i < t; i++) {
		if(mx < __A[i]) {
			mx = __A[i];
		}
		if(mn > __A[i]) {
			mn = __A[i];
		}
	}
	return mx - mn;
}

void answer(int i, int a) {
	__answer_c++;
	if(!(1 <= i && i <= __N)) {
		printf("Wrong Answer\n");
		exit(0);
	}
	if(!(1 <= a && a <= __N)) {
		printf("Wrong Answer\n");
		exit(0);
	}
	if(__used[i - 1]) {
		printf("Wrong Answer\n");
		exit(0);
	}
	if(a != __A[i - 1]) {
		printf("Wrong Answer\n");
		exit(0);
	}
	__used[i - 1] = true;
}

int main() {
	__query_c = 0;
	__answer_c = 0;
	if(scanf("%d", &__N) != 1) {
		fprintf(stderr, "Error while reading input\n");
		exit(1);
	}
	for(int i = 0; i < __N; i++) {
		if(scanf("%d", __A + i) != 1) {
			fprintf(stderr, "Error while reading input\n");
			exit(1);
		}
		__used[i] = false;
	}
	solve(__N);
	if(!(__answer_c == __N)) {
		printf("Wrong Answer\n");
		exit(0);
	}
	printf("Accepted : %d\n", __query_c);
}

#endif

#ifdef LOCAL
#include "template/debug.hpp"
#else
#define dbg(...) ;
#define timer(...) ;
#endif

void solve(int N) {
  int lb = 1, rb = N;
  while (lb < rb) {
    int mid = (lb + rb + 1) / 2;
    if (query(mid, N) != N - 1) {
      rb = mid - 1;
    } else {
      lb = mid;
    }
  }

  // we know A[lb] == 1

  // we will know lb + 1
  
  std::vector<int> filled(N + 1, 0);
  std::vector<int> A(N + 1), D(N + 1, -1);
  A[lb] = 1;
  filled[1] = 1;

  if (lb + 1 <= N) {
    D[lb + 1] = query(lb, lb + 1);
    A[lb + 1] = A[lb] + D[lb + 1];
    filled[A[lb + 1]] = 1;
  }

  if (lb - 1 >= 1) {
    D[lb - 1] = query(lb - 1, lb);
    A[lb - 1] = A[lb] + D[lb - 1];
    filled[A[lb - 1]] = 1;
  }

  for (int L = lb - 2; L >= 1; L--) {
    D[L] = query(L, L + 1);
    A[L] = A[L + 1];
    int vp = A[L] + D[L];
    int vm = A[L] - D[L];
    
    if (vp > N || filled[vp]) {
      A[L] = vm;
    } else if (vm < 1 || filled[vm]) {
      A[L] = vp;
    } else {
      int tie = query(L, L + 2);
      if (tie == D[L] + D[L + 1]) {
        A[L] = (A[L + 1] < A[L + 2]) ? vm : vp; 
      } else {
        A[L] = (A[L + 1] < A[L + 2]) ? vp : vm;
      }
    }

    filled[A[L]] = 1;
  }

  for (int R = lb + 2; R <= N; R++) {
    D[R] = query(R - 1, R);
    A[R] = A[R - 1];

    int vp = A[R] + D[R];
    int vm = A[R] - D[R];

    if (vp > N || filled[vp]) {
      A[R] = vm;
    } else if (vm < 1 || filled[vm]) {
      A[R] = vp;
    } else {
      int tie = query(R - 2, R);
      if (tie == D[R] + D[R - 1]) {
        A[R] = (A[R - 2] < A[R - 1]) ? vp : vm;
      } else {
        A[R] = (A[R - 2] < A[R - 1]) ? vm : vp;
      }
    }

    filled[A[R]] = 1;
  }

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

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