G题几乎相同代码一个能过，一个过不了

//代码1，能过
#include <bits/stdc++.h>

using namespace std;

using ll = long long;

const ll MOD = 1000000007;
const int N = 100005;

int n;
int b[2 * N];
ll ops[101][N];

ll fast_expo(ll a, ll n) {
    ll b = 1;
    while (n) {
        if (n & 1) b = b * a % MOD;
        a = a * a % MOD;
        n >>= 1;
    }
    return b;
}

void solve() {
    cin >> n;
    for (int i = 0; i < 2 * n; i++) {
        cin >> b[i];
    }
    for (int i = 1; i <= 100; i++) {
        for (int j = 1; j <= n; j++) {
            ops[i][j] = ((100 - i) * (ops[i][j - 1]) % MOD + 100) * fast_expo(i, MOD - 2) % MOD;
        }
    }
    for (int i = 1; i <= 100; i++) {
        for (int j = 1; j <= n; j++) {
            ops[i][j] = (ops[i][j] + ops[i][j - 1]) % MOD;
        }
    }
    sort(b, b + 2 * n);
    ll ans = 0;
    for (int i = 0; i < 2 * n; i++) {
        ans += ops[b[i]][i / 2 + 1];
    }
    ans %= MOD;
    cout << ans << endl;
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    solve();
    
    return 0;
}

//代码2，过不了
#include <bits/stdc++.h>

using namespace std;

using ll = long long;

const ll MOD = 1000000007;
const int N = 100005;

int n;
int b[2 * N];
ll ops[101][N];

ll fast_expo(ll a, ll n) {
    ll b = 1;
    while (n) {
        if (n & 1) b = b * a % MOD;
        a = a * a % MOD;
        n >>= 1;
    }
    return b;
}

void solve() {
    cin >> n;
    for (int i = 0; i < 2 * n; i++) {
        cin >> b[i];
    }
    for (int i = 1; i <= 100; i++) {
        for (int j = 1; j <= n; j++) {
            ops[i][j] = ((100 - i) * (ops[i][j - 1]) % MOD + 100) * fast_expo(i, MOD - 2) % MOD;
            ops[i][j] = (ops[i][j] + ops[i][j - 1]) % MOD;
        }
    }
    sort(b, b + 2 * n);
    ll ans = 0;
    for (int i = 0; i < 2 * n; i++) {
        ans += ops[b[i]][i / 2 + 1];
    }
    ans %= MOD;
    cout << ans << endl;
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    solve();
    
    return 0;
}

两个代码唯一的区别在于，代码1的30~39行合并成了代码2的30~35行。

是否是编译器优化时产生了问题？@王清楚