Submission #376247

#	Time	Username	Problem	Language	Result	Execution time	Memory
376247		casperwang	Lamps (JOI19_lamps)	C++14	4 / 100	22 ms	14148 KiB

lamp

#include <bits/stdc++.h>
#define All(x) x.begin(), x.end()
#define pb push_back
using namespace std;
#define debug(args...) kout("[ " + string(#args) + " ]", args)
void kout() { cerr << endl; }
template <class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ',kout(b...); }
template <class T> void pary(T L, T R) { while (L != R) cerr << *L << " \n"[++L==R]; }

const int MAXN = 1000000;
int n;
string a, b;
int cnt;
int pre[MAXN+1];
vector <int> arr;
int ans;

int solve(string a, string b) {
	ans = cnt = 0;
	for (int i = 0; i < n; i++) {
		pre[i] = (i ? pre[i-1] : 0) + (a[i] != b[i]);
		cnt++;
		if (i+1==n || b[i] != b[i+1]) {
			int k = pre[i] - ((i-cnt>=0)?pre[i-cnt]:0);
			if (!k)
				arr.pb(0); // +++
			else if (k == cnt)
				arr.pb(1); // ---
			else if (pre[i]-pre[i-k] == k)
				arr.pb(2); // ++-
			else if (pre[i-cnt+k]-((i-cnt>=0)?pre[i-cnt]:0) == k)
				arr.pb(3); // -++
			else
				arr.pb(4); // other
			cnt = 0;
		}
	}
	bool flag = false;
	for (int i = 0; i < arr.size(); i++) {
		if (arr[i]) {
			if (arr[i] == 1) {
				if (!flag) {
					flag = true;
					ans++;
				}
				arr[i] = 0;
			} else if (arr[i] == 2) {
				if (!flag && (i+1 == arr.size() || arr[i+1] != 2)) {
					arr[i] = 0;
					flag = true;
					ans++;
				}
			} else if (arr[i] == 3) {
				if (flag) {
					arr[i] = 0;
					flag = false;
				}
			}
		} else {
			if (flag) {
				flag = false;
			}
		}
	}
	int x = 0, y = 0;
	for (int i = 0; i < arr.size(); i++) {
		if (arr[i]) {
			if (i % 2) x++;
			else y++;
		} else {
			if (x > y)
				ans += (y + (x > 0));
			else
				ans += (x + (y > 0));
			x = y = 0;
		}
	}
	arr.clear();
	return ans;
}

signed main() {
	ios_base::sync_with_stdio(0), cin.tie(0);
	cin >> n;
	cin >> a >> b;
	cout << solve(a, b) << endl;
}

Compilation message (stderr)

lamp.cpp: In function 'int solve(std::string, std::string)':
lamp.cpp:39:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |  for (int i = 0; i < arr.size(); i++) {
      |                  ~~^~~~~~~~~~~~
lamp.cpp:48:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |     if (!flag && (i+1 == arr.size() || arr[i+1] != 2)) {
      |                   ~~~~^~~~~~~~~~~~~
lamp.cpp:66:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   66 |  for (int i = 0; i < arr.size(); i++) {
      |                  ~~^~~~~~~~~~~~

• Subtask 1: 0 / 6
• Subtask 2: 0 / 41
• Subtask 3: 4 / 4
• Subtask 4: 0 / 49