C++で組み合わせ数を計算するコードを考える

#include <bits/stdc++.h>

using namespace std;
using ll = int64_t;

void comb(vector<vector<ll> > &v) {
    for (int i = 0; i < v.size(); i++) {
        v[i][0] = 1;
        v[i][i] = 1;
    }
    for (int k = 1; k < v.size(); k++) {
        for (int j = 1; j < k; j++) {
            v[k][j] = (v[k - 1][j - 1] + v[k - 1][j]);
        }
    }
}
ll ncr1(ll n, ll r) {
    vector<vector<ll>> v(n + 1, vector<ll>(n + 1, 0));
    comb(v);
    return v[n][r];
}

#include <bits/stdc++.h>

using namespace std;
using ll = int64_t;

ll ncr2(ll n, ll r) {
    if (r > n) return 0;
    if (r * 2 > n) r = n - r;
    if (r == 0) return 1;

    ll result = n;
    for (ll i = 2; i <= r; ++i) {
        result *= (n - i + 1);
        result /= i;
    }
    return result;
}

int main() {

    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    ll MOD = 1000000007;
    for (int i = 100; i < 1000; ++i) {
        for (int j = 0; j < i + 1; ++j) {
            ll c1 = ncr1(i, j);
            ll cc = ncr2(i, j);
            if (c1 != cc) {
                printf("Result not match! on C(%d, %d) -- expected:%lld, actual:%lld \n", i, j, c1, cc);
                exit(0);
            }
        }
    }
    cout << "check finished!" << endl;
}

Result not match! on C(100, 16) -- expected:1345860629046814650, actual:192939124439967674 

Process finished with exit code 0

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    ll MOD = 1000000007;
    for (int i = 1; i < 100; ++i) {
        for (int j = 0; j < i + 1; ++j) {
            ll c1 = ncr1(i, j);
            ll cc = ncr2(i, j);
            if (c1 != cc) {
                printf("Result not match! on C(%d, %d) -- expected:%lld, actual:%lld \n", i, j, c1, cc);
                exit(0);
            }
        }
    }
    cout << "check finished!" << endl;
}

Result not match! on C(62, 28) -- expected:349615716557887465, actual:-309196571788882235