Submission #1032292

#	Time	Username	Problem	Language	Result	Execution time	Memory
1032292		0npata	Painting Walls (APIO20_paint)	C++17	100 / 100	203 ms	19544 KiB

paint

#include "paint.h"

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

#define vec vector

int minimumInstructions(int N, int M, int K, std::vector<int> C, std::vector<int> A, std::vector<std::vector<int>> B) {

	vec<set<int>> b(M);
	for(int i = 0; i<M; i++) {
		for(int j = 0; j<B[i].size(); j++) {
			b[i].insert(B[i][j]);
		}
	}

	vec<int> pref_match(N);
	vec<int> suf_match(N);

	for(int i = 0; i<N; i++) {
		for(int j = 0; j<M; j++) {
			if(i+j == N) break;
			if(!b[j].count(C[i+j])) break;
			pref_match[i]++;
		}
		//cerr << pref_match[i] << ' ';
	}
	//cerr << '\n';

	for(int i = 0; i<N; i++) {
		for(int j = 0; j<M; j++) {
			if(i-j == -1) break;
			if(!b[M-j-1].count(C[i-j])) break;
			suf_match[i]++;
		}
	//		cerr << suf_match[i] << ' ';
	}
	//cerr << '\n';

	int lst = 0;

	int ans = 0;

	while(lst != N) {
		int bst = -1;
		for(int i = max(lst-M+1, 0); i<min(lst+M, N); i++) {
			int need = max(i-lst, 0);
			if(i > 0 && suf_match[i-1] < need) continue;
			if((i > 0 ? min(suf_match[i-1], M-1) : 0) + pref_match[i] < M) continue;
			bst = max(bst, i+min(pref_match[i], M-need));
		}
		if(bst <= lst) return -1;
		lst = bst;
		ans++;
	}

	// JUST TESTING EFFICIENCY OF MY SOLUTION
	long long very_important = 0;
	for(int i = 0; i<N; i++) {
		for(int j = 0; j<M; j++) {
			very_important = i*j;
		}
	}

	return ans+(very_important==9813471812);
}

Compilation message (stderr)

paint.cpp: In function 'int minimumInstructions(int, int, int, std::vector<int>, std::vector<int>, std::vector<std::vector<int> >)':
paint.cpp:12:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |   for(int j = 0; j<B[i].size(); j++) {
      |                  ~^~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 15 / 15
• Subtask 3: 13 / 13
• Subtask 4: 23 / 23
• Subtask 5: 37 / 37