Submission #301242

#	Time	Username	Problem	Language	Result	Execution time	Memory
301242		williamMBDK	Paint By Numbers (IOI16_paint)	C++17	90 / 100	2063 ms	87732 KiB

paint

#include<bits/stdc++.h>
#include "paint.h"
#include <cstdlib>
using namespace std;
const int MN = 200000;
int N, K;
string S;
vector<int> C;
vector<vector<int>> dp (MN + 10, vector<int> (101, -1));
vector<bool> x (MN), w(MN);
int rec(int i1, int i2){
	if(dp[i1][i2] != -1) return dp[i1][i2];
	if(i2 == K){
		dp[i1][i2] = 1;
		for(int i = i1; i < N; i++){
			if(S[i] == 'X'){
				dp[i1][i2] = 0;
			}
		}
		if(dp[i1][i2]){
			for(int i = i1; i < N; i++){
				w[i] = 1;
			}
		}
		return dp[i1][i2];
	}
	dp[i1][i2] = 0;
	for(int i = i1; i + C[i2] - 1 < N; i++){
		bool b = 1;
		for(int j = i; j < i + C[i2]; j++){
			if(S[j] == '_'){
				b = 0;
				break;
			}
		}	
		int t = i + C[i2];
		if(b && (t == N || S[t] != 'X') && rec(i + C[i2] + 1, i2+1)){
			if(t < N){
				w[t] = 1;
			}
			for(int j = i; j < i + C[i2]; j++){
				x[j] = 1;
			}
			for(int j = i1; j < i; j++){
				w[j] = 1;
			}
			for(int j = i1; j <= i; j++){
				dp[j][i2] = 1;
			}
			// optimize this
		}
		if(S[i] == 'X') break;
	}
	//cout << i1 << " " << i2 << " " << dp[i1][i2] << endl;
	return dp[i1][i2];
}
string solve_puzzle(string _s, vector<int> _c) {
	//cout << "input: " << _s << endl;
	S = _s;
	C = _c;
	//for(auto e : C) cout << e << " ";
	//cout << endl;
	N = S.length();
	K = C.size();
	rec(0, 0);
	string res (N, '?');
	for(int i = 0; i < N; i++){
		if(S[i] == 'X') x[i] = 1;
		else if(S[i] == '_') w[i] = 1;
		if(w[i] == 0 && x[i] == 0) w[i] = 1;
		if(x[i] && !w[i]) res[i] = 'X';
		else if(!x[i] && w[i]) res[i] = '_';
	}
	return res;
}

• Subtask 1: 7 / 7
• Subtask 2: 3 / 3
• Subtask 3: 22 / 22
• Subtask 4: 27 / 27
• Subtask 5: 21 / 21
• Subtask 6: 10 / 10
• Subtask 7: 0 / 10