Submission #330926

#	Time	Username	Problem	Language	Result	Execution time	Memory
330926		ZwariowanyMarcin	K-th path (IZhO11_kthpath)	C++14	100 / 100	1 ms	512 KiB

kthpath

#include <bits/stdc++.h>
#define pb push_back
#define fi first
#define se second
#define sz(x) (int)x.size()

using ll = long long;
using namespace std;

const int N = 100;
const ll INF = 1LL << 60;

void add(ll &a, ll b) {
	a += b;
	a = min(a, INF);
}

ll qq(ll a, ll b) {
	if (a > INF / b) return INF;
	return a * b;
}

int n, m;
char s[N][N];
ll dp[N][N], k, C[N][N];
vector <pair<int, int>> lvl[N];

int main() {
	for (int i = 0; i < N; ++i) {
		C[i][0] = C[i][i] = 1;
		for (int j = 1; j < i; ++j)
			C[i][j] = min(C[i - 1][j - 1] + C[i - 1][j], INF);
	}
	scanf("%d%d", &n, &m);
	for (int i = 1; i <= n; ++i) {
		scanf("%s", s[i] + 1);
		for (int j = 1; j <= m; ++j)
			lvl[i + j].pb({i, j});
	}
	scanf("%lld", &k);
	dp[1][1] = 1;
	printf("%c", s[1][1]);
	for (int i = 3; i <= n + m; ++i) {
		ll cnt[26]{};
		for (auto [r, c] : lvl[i]) {
			int x = n - r, y = m - c;
			add(cnt[s[r][c] - 'a'], qq(dp[r - 1][c] + dp[r][c - 1], C[x + y][x]));
		}
		for (int c = 0; c < 26; ++c) {
			if (cnt[c] < k) {
				k -= cnt[c];
				continue;
			}
			for (auto [r, k] : lvl[i])
				if (s[r][k] - 'a' == c)
					dp[r][k] = min(INF, dp[r - 1][k] + dp[r][k - 1]);
			printf("%c", (char)('a' + c));
			break;
		}
	}
	
	return 0;
}

Compilation message (stderr)

kthpath.cpp: In function 'int main()':
kthpath.cpp:45:13: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   45 |   for (auto [r, c] : lvl[i]) {
      |             ^
kthpath.cpp:54:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   54 |    for (auto [r, k] : lvl[i])
      |              ^
kthpath.cpp:34:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   34 |  scanf("%d%d", &n, &m);
      |  ~~~~~^~~~~~~~~~~~~~~~
kthpath.cpp:36:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   36 |   scanf("%s", s[i] + 1);
      |   ~~~~~^~~~~~~~~~~~~~~~
kthpath.cpp:40:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   40 |  scanf("%lld", &k);
      |  ~~~~~^~~~~~~~~~~~

• Subtask 1: 100 / 100