Submission #1020782

#	Time	Username	Problem	Language	Result	Execution time	Memory
1020782		Minbaev	K-th path (IZhO11_kthpath)	C++17	100 / 100	1 ms	464 KiB

kthpath

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
 
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimize("Ofast,unroll-loops")
 
using namespace std;
using namespace __gnu_pbds;
 
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define f first
#define s second
#define int long long
#define pii pair<int,int>
 
template<class T>bool umax(T &a,T b){if(a<b){a=b;return true;}return false;}
template<class T>bool umin(T &a,T b){if(b<a){a=b;return true;}return false;}
 
template<class T>
using Tree = tree<T, null_type, less<T>, rb_tree_tag,
    tree_order_statistics_node_update>;
 
const int inf = 1e17 + 7;
const int mod = 1e9 + 7;
const int N = 3e5 + 5;

int binpow(int a, int b){
	if(b == 0)return 1;
	if(b % 2 == 0){
		int c = binpow(a,b/2);
		return (c*c);
	}
	return (binpow(a,b-1)*a);
}

int divi(int a, int b){
	return (a*(binpow(b,mod-2)))%mod;
}

int n,m,k;
int len;
char arr[35][35], ans[900];
int dp[35][35];

int dfs(int x, int y){
	int pos = x+y;
	if(ans[pos-2] != '*' && ans[pos-2] != arr[x][y])return 0;
	if(x == n && y == m)return 1;
	
	if(dp[x][y] > -1)return dp[x][y];
	
	dp[x][y] = 0;
	if(x + 1 <= n)dp[x][y] += dfs(x+1,y);
	if(y + 1 <= m)dp[x][y] += dfs(x,y+1);
	
	return dp[x][y];
}

void solve(){
	
	cin >> n >> m;
	len = n + m - 1;
	
	for(int i = 1;i<=n;i++){
		for(int j = 1;j<=m;j++){
			cin >> arr[i][j];
		}
	}
	
	cin >> k;
	for(int i = 0;i<len;i++)ans[i] = '*';
	
	ans[0] = arr[1][1];
	
	for(int i = 1;i<len;i++){
		for(int j = 0;j<26;j++){
			ans[i] = j+'a';
			memset(dp, -1, sizeof(dp));
			
			if(dfs(1,1)>=k)break;
			k -= dfs(1,1);
			
			
		}
	}
	
	for(int i = 0;i<len;i++)cout << ans[i];
	
}
 
 signed main()
{
//	freopen("seq.in", "r", stdin);
//  freopen("seq.out", "w", stdout);

	ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL);
	int tt=1;//cin>>tt;
	while(tt--)solve();
 
}
 

• Subtask 1: 100 / 100