Submission #107173

#	Time	Username	Problem	Language	Result	Execution time	Memory
107173		eriksuenderhauf	Lamps (JOI19_lamps)	C++11	100 / 100	83 ms	14840 KiB

lamp

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define mem(a,v) memset((a), (v), sizeof (a))
#define enl printf("\n")
#define case(t) printf("Case #%d: ", (t))
#define ni(n) scanf("%d", &(n))
#define nl(n) scanf("%lld", &(n))
#define nai(a, n) for (int i = 0; i < (n); i++) ni(a[i])
#define nal(a, n) for (int i = 0; i < (n); i++) nl(a[i])
#define pri(n) printf("%d\n", (n))
#define prl(n) printf("%lld\n", (n))
#define pii pair<int, int>
#define pil pair<int, long long>
#define pll pair<long long, long long>
#define vii vector<pii>
#define vil vector<pil>
#define vll vector<pll>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef cc_hash_table<int,int,hash<int>> ht;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> oset;
const double pi = acos(-1);
const int MOD = 1e9 + 7;
const int INF = 1e9 + 7;
const int MAXN = 1e6 + 5;
const double eps = 1e-9;
char a[MAXN], b[MAXN];
int dp[MAXN][3];

char f(char cur, int type) {
	if (type == 0)
		return '0';
	else if (type == 1)
		return '1';
	return cur;
}

int main() {
	int n;
	scanf("%d %s %s", &n, a+1, b+1);
	dp[0][0] = dp[0][1] = INF;
	for (int i = 1; i <= n; i++) {
		for (int j = 0; j < 3; j++)
			dp[i][j] = INF;
		for (int j = 0; j < 3; j++) {
			for (int k = 0; k < 3; k++) {
				int cost = 0;
				if (j != k && j != 2)
					cost++;
				if ((i == 1 || f(a[i-1], k) == b[i-1]) && f(a[i], j) != b[i])
					cost++;
				dp[i][j] = min(dp[i][j], dp[i-1][k] + cost);
			}
		}
	}
	pri(min(dp[n][0], min(dp[n][1],dp[n][2])));
    return 0;
}

Compilation message (stderr)

lamp.cpp: In function 'int main()':
lamp.cpp:49:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %s %s", &n, a+1, b+1);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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