CSP-S 提高级 初赛 模拟试卷（三）

#include <iostream>
using namespace std;
int main() {
    int n = 5, total = 0;
    for (int mask = 0; mask < (1 << n); mask++) {
        int bits = 0;
        for (int i = 0; i < n; i++)
            if (mask & (1 << i)) bits++;
        if (bits == 2) total++;
    }
    cout << total << endl;
    return 0;
}

#include <iostream>
using namespace std;
int main() {
    int n = 6;
    int f[10] = {0};
    f[1] = 1; f[2] = 2;
    for (int i = 3; i <= n; i++) f[i] = f[i - 1] + f[i - 2];
    cout << f[n] << endl;
    return 0;
}

#include <iostream>
using namespace std;
int lcm(int a, int b) {
    int x = a, y = b;
    while (y) { int t = x % y; x = y; y = t; }
    return a * b / x;
}
int main() {
    cout << lcm(12, 18) << endl;
    return 0;
}

int gcd(int a, int b) {
    while (b != 0) {
        int t = ① ;   // 余数
        ② ;            // a 更新为 b
        ③ ;            // b 更新为余数
    }
    ④ ;              // 返回结果
}

void bubbleSort(int a[], int n) {
    for (int i = 0; i < n - 1; i++) {
        for (int j = 0; ① ; j++) {   // 每趟范围
            if (②) {                  // 逆序则交换
                int t = a[j];
                a[j] = a[j + 1];
                a[j + 1] = t;
            }
        }
    }
}