腾讯笔试

using namespace std;
int (){
    unsigned long long n,m;
    cin>>n>>m;
    cout<<n/2*m<<endl;
}

#include <iostream>

using namespace std;
const int N = 1000;
const int MOD = (int) 1e9 + 7;
unsigned long long comb[N][N];

void init() {
    for (int i = 0; i < N; i++) {
        comb[i][0] = comb[i][i] = 1;
        for (int j = 1; j < i; j++) {
            comb[i][j] = comb[i - 1][j] + comb[i - 1][j - 1];
            comb[i][j] %= MOD;
        }
    }
}

int () {
    init();
    int k;
    int A, X, B, Y;
    cin >> k >> A >> X >> B >> Y;
    int n = k / A, m = k / B, res;
    unsigned long long ans = 0;
    for (int i = 0; i <= n && i <= X; ++i)
        for (int j = 0; j <= m && j <= Y; ++j)
            if (i * A + j * B == k)
                ans = (ans + comb[X][i] * comb[Y][j] % MOD) % MOD;
    cout << ans;
}

#include<stdio.h>
void test(long long a[]){
    printf("%dn",sizeof(a)/sizeof(long long));
}
int (){
    long long a[]={2,345,2423,4,454};
    printf("%dn",sizeof(a)/sizeof(long long));
    test(a);
}
//结果 5 1

void test(int a[]){
    printf("%dn",sizeof(a)/sizeof(int));
}
int (){
    int a[]={2,345,2423,4,454};
    printf("%dn",sizeof(a)/sizeof(int));
    test(a);
}
//结果5 2 
//因为以 longlong指针传入