Submission #1206894

#	Time	Username	Problem	Language	Result	Execution time	Memory
1206894		nguyn	Lamps (JOI19_lamps)	C++20	100 / 100	52 ms	31676 KiB

lamp

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

#define ll long long 
#define F first
#define S second
#define pb push_back 
#define pii pair<int,int>

const int N = 1e6 + 5;

int n;
int a[N], b[N];
int f[N][3][2]; 

signed main(){
    ios_base::sync_with_stdio(false) ; 
    cin.tie(0) ; cout.tie(0) ; 
    if (fopen("INP.INP" ,"r")) {
        freopen("INP.INP" ,"r" , stdin) ;
        freopen("OUT.OUT" , "w" , stdout) ;
    }
    cin >> n;
    for (int i = 1; i <= n; i++) {
    	char x; cin >> x; 
    	a[i] = (x == '1' ? 1 : 0); 
    }
    for (int i = 1; i <= n; i++) {
    	char x; cin >> x; 
    	b[i] = (x == '1' ? 1 : 0); 
    }
    for (int i = 0; i <= n; i++) {
    	for (int j = 0; j < 3; j++) {
    		for (int k = 0; k < 2; k++) {
    			f[i][j][k] = 1e9; 
    		}
    	}
    }
    f[0][0][0] = 0;
    for (int i = 1; i <= n; i++) {
    	for (int j = 0; j < 3; j++) {
    		for (int k = 0; k < 2; k++) {
    			int cur = a[i]; 
    			if (j == 1) cur = 0;
    			if (j == 2) cur = 1;
    			if (k == 1) cur ^= 1; 
    			if (cur != b[i]) continue;
    			for (int jj = 0; jj < 3; jj++) {
    				for (int kk = 0; kk < 2; kk++) {
    					f[i][j][k] = min(f[i][j][k], f[i - 1][jj][kk] + (j > 0 && j != jj) + (k > 0 && k != kk)); 
    				}
    			} 
    		}
    	}
    }
    int res = 1e9; 
    for (int i = 0; i < 3; i++) {
    	for (int j = 0; j < 2; j++) {
    		res = min(res, f[n][i][j]);
    	}
    }
    cout << res;
}

Compilation message (stderr)

lamp.cpp: In function 'int main()':
lamp.cpp:20:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |         freopen("INP.INP" ,"r" , stdin) ;
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
lamp.cpp:21:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |         freopen("OUT.OUT" , "w" , stdout) ;
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 41 / 41
• Subtask 3: 4 / 4
• Subtask 4: 49 / 49