为什么对f_tim[]进行初始化是错的?

#include <bits/stdc++.h>
using namespace std;
#define oo 2147483648ll
typedef long long ll;
typedef pair<ll, ll> pll;
const ll N = 2e2 + 5, M = 1e4 + 5, mod = 7;
ll n, m, r, rmb[N], tim[N], rp[N], f_tim[N][N], f_num[N][N];
void solve()
{

    cin >> n;
    for (ll i = 1; i <= n; i++)
        cin >> rmb[i] >> rp[i] >> tim[i];
    cin >> m >> r;
    // memset(f_tim, 0x3f, sizeof(f_tim));
    // f_tim[0][0] = 0;//加上这两句话就错了,为什么?
    for (ll i = 1; i <= n; i++)
    {
        for (ll j = m; j >= rmb[i]; j--)
        {
            for (ll k = r; k >= rp[i]; k--)
            {
                if (f_num[j][k] < f_num[j - rmb[i]][k - rp[i]] + 1)
                {
                    f_tim[j][k] = f_tim[j - rmb[i]][k - rp[i]] + tim[i];
                    f_num[j][k] = f_num[j - rmb[i]][k - rp[i]] + 1;
                }
                else if (f_num[j][k] == f_num[j - rmb[i]][k - rp[i]] + 1)
                    f_tim[j][k] = min(f_tim[j][k], f_tim[j - rmb[i]][k - rp[i]] + tim[i]);
            }
        }
    }

    cout << f_tim[m][r] << endl;
}

int main()
{
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    ll TTT = 1;
    // cin >> TTT;
    while (TTT--)
    {
        solve();
    }

    return 0;
}