C++信息学奥赛一本通-第一部分-基础一-第2章-第5节

C++信息学奥赛一本通-第一部分-基础一-第2章-第5节

2070 数字对调

#include <iostream>

using namespace std;

int main() {
    int number; cin >> number;
    int a = number / 100;
    int b = number / 10 % 10;
    int c = number % 100 % 10;
    int target = c * 100 + b * 10 + a;
    cout << target;
}

2071 平均分

#include <iostream>

using namespace std;

int main() {
    double x, y; cin >> x >> y;
    double sum_x = x * 87, sum_y = y * 85;
    double result = (sum_x + sum_y) / (x + y);
    printf("%.4f", result);
}

2072 歌手大奖赛-增幅减幅都一样那平均不还是一样

#include <iostream>

using namespace std;

int main() {
    double a = 9.6;
    printf("%5.2f", a);
}

2073 三角形面积

#include <iostream>
#include <cmath>

using namespace std;

int main() {
    double x, y, z; cin >> x >> y >> z;
    double p = (x+y+z) / 2.0;
    double temp = p * (p - x) * (p - y) * (p - z);
    double s = pow(temp, 0.5);
    printf("%.3f", s);
}

1029 计算浮点数相除的余

#include <iostream>

using namespace std;

int main() {
    double x, y; cin >> x >> y ;
    double nums = x / y;
    double remainder = x - (int)nums * y;
    cout << remainder;
}

1030 计算球的体积-保留小数会四舍五入

#include <iostream>
#define PI 3.14

using namespace std;

int main() {
    double r; cin >> r;

    double V = (PI * r * r *r) * 4 / 3;
    printf("%.2f", V);
}

1031 反向输出一个三位数-和2070的区别就是补0

#include <iostream>

using namespace std;

int main() {
    int number; cin >> number;
    int a = number / 100;
    int b = number / 10 % 10;
    int c = number % 100 % 10;
    int target = c * 100 + b * 10 + a;
    printf("%03d", target);
}

1032 大象喝水查

#include <iostream>
#define PI 3.14

using namespace std;

int main() {
    double h, r; cin >> h >> r;

    double V = (PI * r * r) * h;

    int nums = (int)(20000 / V);
    printf("%d", nums + 1);
}

1033 计算线段长度

#include <iostream>
#include <cmath>
using namespace std;

int main() {
    double xofa, yofa, xofb, yofb; cin >> xofa >> yofa >> xofb >> yofb;
    double result = pow(pow(yofb - yofa ,2)+pow(xofb - xofa , 2), 0.5);
    printf("%.3f",result);
}

1034 计算三角形面积

​ 使用行列式公式计算三角形面积-背的出来就用吧

xa:yb-yc xb:yc - ya xc: ya - yb

#include <iostream>
#include <cmath>

using namespace std;
double calculateTriangleArea(double xofa, double yofa, double xofb, double yofb, double xofc, double yofc) {
    double area = 0.5 * abs((xofa*(yofb - yofc) + xofb*(yofc - yofa) + xofc*(yofa - yofb)));
    return area;
}
int main() {
    double xofa, yofa, xofb, yofb, xofc, yofc; cin >> xofa >> yofa >> xofb >> yofb >> xofc >> yofc;
    double result = calculateTriangleArea(xofa, yofa, xofb, yofb, xofc, yofc);
    printf("%.2f", result);
}

使用向量-推荐

#include <iostream>
#include <cmath>
using namespace std;
double calculateTriangleArea(double xofa, double yofa, double xofb, double yofb, double xofc, double yofc) {
    double vecAB_x = xofb - xofa;
    double vecAB_y = yofb - yofa;
    double vecAC_x = xofc - xofa;
    double vecAC_y = yofc - yofa;

    double cross_product = vecAB_x * vecAC_y - vecAB_y * vecAC_x;


    return 0.5 * fabs(cross_product);
}

int main() {
    double xofa, yofa, xofb, yofb, xofc, yofc; cin >> xofa >> yofa >> xofb >> yofb >> xofc >> yofc;
    double result = calculateTriangleArea(xofa, yofa, xofb, yofb, xofc, yofc);
    printf("%.2f", result);
}

1035 等差数列末项计算

#include <iostream>

using namespace std;

int main() {
    int n_of_1, n_of_2, n; cin >> n_of_1 >> n_of_2 >> n;
    int result = (n_of_2 - n_of_1) * (n-1) + n_of_1;
    cout << result;
}

1036 $A\ast B$问题

unsigned int 最高42亿

#include <iostream>

using namespace std;

int main() {
    unsigned int a, b; cin >> a >> b;

    unsigned int result = a * b;

    cout << result;
}

1037 计算2的幂

#include <iostream>
#include <cmath>
using namespace std;

int main() {
    unsigned int n; cin >> n;
    
    unsigned int result = pow(2,n);

    cout << result;
}

1038 苹果和虫子

#include <iostream>

using namespace std;

int main() {
    int n, x, y; cin >> n >> x >> y;
    int result = (y % x == 0) ? (n - (y / x)) : (n - (y / x) - 1);
    if (result < 0) result = 0;
    cout << result;
}