백준 13703번 물벼룩의 생존확률 C++

https://www.acmicpc.net/problem/13703

13703번: 물벼룩의 생존확률

 

다이나믹 프로그래밍

 

#include <iostream>
#include <string>
#include <vector>
#include <math.h>
#include <algorithm>
#include <utility>
#include <stack>
#include <queue>
#include <math.h>
#include <set>
#include <map>
#include <list>
#include <unordered_map>
#include <unordered_set>
#include <iomanip>
#include <limits.h>

using namespace std;
using int64 = long long; 

int k, n;
vector<vector<int64>> cache;

int64 dp(int height, int time) {
    int64& val = cache[height][time];
    if (val != -1) return val;
    if (height == 0) return val = 0;
    if (time == 0) return val = 1;
    val = 0;
    return val = dp(height - 1, time - 1) + dp(height + 1, time - 1);
}

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

    cin >> k >> n;
    cache = vector<vector<int64>>(128, vector<int64>(128, -1));
    int64 ans = dp(k, n);
    cout << ans;
}