Submission #338501

#	Time	Username	Problem	Language	Result	Execution time	Memory
338501		talant117408	K-th path (IZhO11_kthpath)	C++17	100 / 100	2 ms	384 KiB

kthpath

/*
    Code written by Talant I.D.
*/
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
 
//using namespace __gnu_pbds;
using namespace std;
 
//typedef tree <int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
typedef long long ll;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;
  
#define precision(n) fixed << setprecision(n)
#define pb push_back
#define ub upper_bound
#define lb lower_bound
#define mp make_pair
#define eps (double)1e-9
#define PI 2*acos(0.0)
#define endl "\n"
#define sz(v) int((v).size())
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define do_not_disturb ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define OK cout << "OK" << endl;
  
inline bool isvowel(char ch){
    ch = tolower(ch);
    return (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u');
}
  
inline bool isprime(int n){
    if(n < 2 || (n%2 == 0 && n != 2)) return false;
    for(int i = 3; i*i <= n; i++)
        if(n%i == 0) return false;
    return true;
}
 
class Union{
    private:
        vector <int> saizu, link;
    public:
        Union(int n){
            saizu.assign(n, 1); link.resize(n); 
            iota(all(link), 0);
        }
        int find(int n){
            if(link[n] == n) return n;
            return link[n] = find(link[n]);
        }
        int same(int a, int b){
            return find(a) == find(b);
        }
        void unite(int a, int b){
            if(same(a, b)) return;
             
            a = find(a); b = find(b);
            if(saizu[a] < saizu[b]) swap(a, b);
             
            saizu[a] += saizu[b];
            link[b] = a;
        }
        int getsize(int a){
            return saizu[find(a)];
        }
};
 
const int mod = 1e9+7;
 
ll mode(ll a){
    a %= mod;
    if(a < 0) a += mod;
    return a;
}
 
ll subt(ll a, ll b){
    return mode(mode(a)-mode(b));
}
 
ll add(ll a, ll b){
    return mode(mode(a)+mode(b));
}
 
ll mult(ll a, ll b){
    return mode(mode(a)*mode(b));
}
 
ll binpow(ll a, ll b){
    ll res = 1;
    while(b){
        if(b&1) res = mult(res, a);
        a = mult(a, a);
        b >>= 1;
    }
    return res;
}

const int N = 35;
string ans = "";
int n, m;
ll dp[N][N];
char grid[N][N];
ll k;

ll rec(int x, int y){
    int pos = x+y-1;
    if(ans[pos] != grid[x][y] && ans[pos] != ' ') return 0;
    if(x == n && m == y) return 1ll;
    if(dp[x][y] != -1) return dp[x][y];
    
    ll res = 0;
    if(x < n) res += rec(x+1, y);
    if(y < m) res += rec(x, y+1);
    return dp[x][y] = res;
}

int main(){
    do_not_disturb
    
    cin >> n >> m;
    for(int i = 1; i <= n; i++){
        for(int j = 1; j <= m; j++){
            cin >> grid[i][j];
        }
    }
    cin >> k;
    
    for(int i = 0; i <= n+m-1; i++) ans += ' ';
    
    ans[1] = grid[1][1];
    for(int i = 2; i <= n+m-1; i++){
        for(char j = 'a'; j <= 'z'; j++){
            ans[i] = j;
            memset(dp, -1, sizeof(dp));
            auto paths = rec(1, 1);
            if(paths >= k) break;
            k -= paths;
        }
    }
    
    ans.erase(ans.begin());
    cout << ans;
    
    return 0;
}

• Subtask 1: 100 / 100