Submission #1090010

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
1090010	2024-09-17T14:16:43 Z	xnqs	K-th path (IZhO11_kthpath)	C++17	100 / 100	54 ms	600 KB

kthpath

#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
#include <functional>

int x, y;
int64_t k;
char arr[30][31];

int64_t count_solutions(const std::string& tgt) {
	std::vector<std::vector<std::vector<int64_t>>> dp(x,std::vector<std::vector<int64_t>>(y,std::vector<int64_t>(2,-1)));

	const std::function<int64_t(int,int,int)> sol = [&](int i, int j, int tight) {
		if (i==x-1&&j==y-1) {
			return static_cast<int64_t>(1);
		}
		if (dp[i][j][tight]!=-1) {
			return dp[i][j][tight];
		}

		int64_t ret = 0;
		if (i+1<x &&
		    ((tight) ? arr[i+1][j]<=tgt[i+1+j] : 1)) {
			ret += sol(i+1,j,tight&(arr[i+1][j]==tgt[i+1+j]));
		}
		if (j+1<y &&
		    ((tight) ? arr[i][j+1]<=tgt[i+j+1] : 1)) {
			ret += sol(i,j+1,tight&(arr[i][j+1]==tgt[i+j+1]));
		}

		return dp[i][j][tight] = ret;
	};

	return sol(0,0,1);
}

int main() {
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(NULL);
	std::cout.tie(NULL);

	std::cin >> x >> y;
	for (int i = 0; i < x; i++) {
		std::cin >> arr[i];
	}
	std::cin >> k;

	std::string tgt(x+y-1,'z');
	tgt[0] = arr[0][0];
	tgt[x+y-2] = arr[x-1][y-1];

	for (int i = 1; i < x+y-2; i++) {
		char best = 'z';
		for (int j = 'z'; j >= 'a'; j--) {
			tgt[i] = j;
			if (count_solutions(tgt)>=k) {
				best = j;
			}
		}

		tgt[i] = best;
	}

	std::cout << tgt << "\n";
}

Subtask #1

100.0 / 100.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	0 ms	344 KB	Output is correct
2	Correct	0 ms	348 KB	Output is correct
3	Correct	1 ms	348 KB	Output is correct
4	Correct	4 ms	348 KB	Output is correct
5	Correct	1 ms	348 KB	Output is correct
6	Correct	4 ms	344 KB	Output is correct
7	Correct	6 ms	456 KB	Output is correct
8	Correct	6 ms	348 KB	Output is correct
9	Correct	1 ms	348 KB	Output is correct
10	Correct	17 ms	484 KB	Output is correct
11	Correct	5 ms	464 KB	Output is correct
12	Correct	19 ms	600 KB	Output is correct
13	Correct	28 ms	348 KB	Output is correct
14	Correct	27 ms	496 KB	Output is correct
15	Correct	46 ms	348 KB	Output is correct
16	Correct	54 ms	348 KB	Output is correct
17	Correct	49 ms	344 KB	Output is correct
18	Correct	49 ms	348 KB	Output is correct
19	Correct	52 ms	344 KB	Output is correct
20	Correct	51 ms	352 KB	Output is correct