Submission #6259868

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

#define N 1000000
#define MOD 998244353

int fpow(int x, int p) {
    int ret = 1;
    while (p) {
        if (p & 1) ret = 1LL * ret * x % MOD;
        x = 1LL * x * x % MOD;
        p >>= 1;
    }
    return ret;
}

int n, m, fac[N + 5], facinv[N + 5];

int C(int n, int m) {
    return 1LL * fac[n] * facinv[m] % MOD * facinv[n - m] % MOD;
}

int main() {
    fac[0] = 1;
    for (int i = 1; i <= N; ++i) fac[i] = 1LL * fac[i - 1] * i % MOD;
    facinv[N] = fpow(fac[N], MOD - 2);
    for (int i = N; i >= 1; --i) facinv[i - 1] = 1LL * facinv[i] * i % MOD;
    scanf("%d%d", &n, &m);
    if (n < m) swap(n, m);
    int ans = 0;
    for (int i = 1; i <= m; ++i)
        ans = (ans + 1LL * C(2 * i, i) * C(n + m - 2 * i, n - i) % MOD) % MOD;
    ans = 1LL * ans * fpow(2, MOD - 2) % MOD * fpow(C(n + m, n), MOD - 2) % MOD;
    ans = (ans + n) % MOD;
    printf("%d\n", ans);
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:29:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &m);
                          ^

Judge Result