Submission #8475265

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Source Code Expand

#include <cstdio>

using namespace std;

const int mod = 1'000'000'007;

int mul(int a, int b) {
  return (int)((long long)a * b % mod);
}

int pw(int a, int b) {
  int res = 1;
  while (b > 0) {
    if (b % 2 == 1) {
      res = mul(res, a);
    }
    a = mul(a, a);
    b /= 2;
  }
  return res;
}

int inv(int a) {
  return pw(a, mod - 2);
}

const int N = 1'000'009;

int f[N];
int rf[N];

int choose(int n, int k) {
  return mul(f[n], mul(rf[k], rf[n - k]));
}

int main() {
  f[0] = 1;
  rf[0] = 1;
  for (int i = 1; i < N; ++i) {
    f[i] = mul(f[i - 1], i);
    rf[i] = inv(f[i]);
  }
  int x, y;
  scanf("%d%d", &x, &y);
  int i = 1;
  while (i <= x && i <= y) {
    if ((x - i) + (y - i) == i) {
      break;
    }
    ++i;
  }
  printf("%d\n", i > x || i > y ? 0 : choose(i, x - i));
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:44:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &x, &y);
                        ^

Judge Result