Submission #173387

#	Time	Username	Problem	Language	Result	Execution time	Memory
173387		ZwariowanyMarcin	Lamps (JOI19_lamps)	C++14	100 / 100	35 ms	16040 KiB

lamp

#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define ss(x) (int) x.size()
#define pb push_back
#define ll long long
#define cat(x) cerr << #x << " = " << x << endl
#define FOR(i, n) for(int i = 0; i < n; ++i)

using namespace std;	

const int nax = 1e6 + 111;

void mini(int &a, int b) {
	a = min(a, b);
}

int n;
char a[nax];
char b[nax];

int t[nax][3];
			
int main() {
	a[0] = b[0] = '#';
	scanf("%d", &n);
	scanf("%s", a + 1);
	scanf("%s", b + 1);
	
	t[0][0] = 0;
	t[0][1] = n;
	t[0][2] = n;
	
	for(int i = 1; i <= n; ++i) {
		t[i][0] = t[i][1] = t[i][2] = n;
		// 0
		mini(t[i][0], t[i - 1][0] + (a[i] != b[i] && a[i - 1] == b[i - 1]));
		mini(t[i][0], t[i - 1][1] + (a[i] != b[i] && b[i - 1] == '1'));
		mini(t[i][0], t[i - 1][2] + (a[i] != b[i] && b[i - 1] == '0'));
		// 1
		mini(t[i][1], t[i - 1][0] + 1 + (b[i] == '0' && a[i - 1] == b[i - 1]));
		mini(t[i][1], t[i - 1][1] + (b[i] == '0' && b[i - 1] == '1'));
		// 2
		mini(t[i][2], t[i - 1][0] + 1 + (b[i] == '1' && a[i - 1] == b[i - 1]));
		mini(t[i][2], t[i - 1][2] + (b[i] == '1' && b[i - 1] == '0'));
		//printf("%d %d %d %d\n", i, t[i][0], t[i][1], t[i][2]);
	} 
	printf("%d", min({t[n][0], t[n][1], t[n][2]}));

	return 0;
}

Compilation message (stderr)

lamp.cpp: In function 'int main()':
lamp.cpp:27:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ~~~~~^~~~~~~~~~
lamp.cpp:28:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s", a + 1);
  ~~~~~^~~~~~~~~~~~~
lamp.cpp:29:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s", b + 1);
  ~~~~~^~~~~~~~~~~~~

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