動的計画法の練習(Combination)

DP_sample(cases).cpp

#include <stdio.h>
#include <algorithm>
using namespace std;

int memo[30][30];
int dp(int i, int j)
{
    if(memo[i][j] != -1)
        return memo[i][j];
    else if(i == 0 || j == 0)
        return memo[i][j] = 1;
    else
        return memo[i][j] = dp(i-1, j) + dp(i, j-1);
}

int main()
{
    int h, w;
    scanf("%d %d", &h, &w);
    fill(memo[0], memo[h], -1);
    printf("%d", dp(h-1, w-1));
    return 0;
}