Submission #41185

#	Time	Username	Problem	Language	Result	Execution time	Memory
41185		alenam0161	K-th path (IZhO11_kthpath)	C++14	0 / 100	728 ms	262144 KiB

kthpath

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
using namespace std;
const int N = 3e3 + 7;
long long dp[N][N];
string a[N];
long long C[N];
int main() {
	//freopen("input.txt", "r", stdin);
	int n, m;
	cin >> n >> m;
	for (int i = 0; i < n; ++i)cin >> a[i];
	for(int i=n-1;i>=0;i--)
		for (int j = m - 1; j >= 0; j--) {
			if (i == n - 1 && j == m - 1)dp[i][j] = 1;
			else dp[i][j] = dp[i + 1][j] + dp[i][j + 1];
		}
	long long k;
	cin >> k;
	string ans = "";
	vector<pair<int, int>> v,cur;
	v.push_back({ 0,0 });
	for (int i = 0; i < (n + m)-1; ++i) {
		for (int j = 0; j < 26; ++j)C[j] = 0;
		if (i == 0) {
			ans += a[v[0].first][v[0].second];
		}
		for (int j = 0; j < v.size(); ++j) {
			if (v[j].first + 1 < n) {
				C[a[v[j].first + 1][v[j].second]-'a'] += dp[v[j].first + 1][v[j].second];
			}
			if (v[j].second + 1 < m) {
				C[a[v[j].first][v[j].second + 1]-'a'] += dp[v[j].first][v[j].second + 1];
			}
		}
		for (int j = 0; j < 26; ++j) {
			if (C[j] < k) {
				k -= C[j];
			}
			else {
				ans += char(j + 'a');
				cur.clear();
				for (int c = 0; c < v.size(); ++c) {
					if (v[c].first + 1 < n&&a[v[c].first + 1][v[c].second] - 'a' == j) {
						cur.push_back({ v[c].first + 1,v[c].second });
					}
					if (v[c].second + 1 < m&&a[v[c].first][v[c].second + 1] - 'a' == j) {
						cur.push_back({ v[c].first,v[c].second + 1 });
					}
				}
				v = cur;
				break;
			}
		}
	}
	cout << ans << endl;
	return 0;
}

Compilation message (stderr)

kthpath.cpp: In function 'int main()':
kthpath.cpp:31:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int j = 0; j < v.size(); ++j) {
                     ^
kthpath.cpp:46:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int c = 0; c < v.size(); ++c) {
                       ^

• Subtask 1: 0 / 100