一、问题描述
二、解答
方法一：分类型遍历所有点
#include<iostream>
using namespace std;
char type[10000000] = { NULL };//字符型数组初始化
int x[10000000] = { 0 };
int y[10000000] = { 0 };//写在外面
int main()
{int m, n;cin >> n >> m;int o[20] = { 0 };int p[20] = { 0 }; int q[20] = { 0 };for (int i = 0; i < n; i++){cin >> x[i] >> y[i] >> type[i];}for (int j = 0; j < m; j++){cin >> o[j] >> p[j] >> q[j];}for (int j = 0; j < m; j++){ int bigA = 0;//状态为A时大于0int smallA = 0;//状态为A时小于0int bigB = 0;//状态为B时大于0int smallB = 0;//状态为B时小于0for (int i = 0; i < n; i++){if (type[i] == 'A')//！！！注意：在条件语句中，应该使用双等号(==)进行比较，而不是单个等号(=){int proA = o[j] + p[j] * x[i] + q[j] * y[i];if(proA>0){bigA++;}else if (proA < 0){smallA++;}}else if (type[i] == 'B'){int proB = o[j] + p[j] * x[i] + q[j] * y[i];if (proB > 0){bigB++;}else if (proB < 0){smallB++;}}}if ((smallA==0&&bigA>0&&smallB>0&&bigB==0)|| (smallA> 0 && bigA == 0 && smallB == 0 && bigB > 0)){cout << "Yes" << endl;}else{cout << "No" << endl;}}return 0;
}
方法二：创建结构体
#include<iostream>
using namespace std;
//创建结构体
struct Point {int x;int y;char type;
};
struct Line {int o1;int o2;int o3;
};
int main()
{int m, n;cin >> n >> m;struct Point *p;p = new struct Point[n];//使用了动态内存分配 newstruct Line *l;l = new struct Line[m];//struct Point points[n];这样写会报错“表达式必须有常量值”//因为使用了静态数组声明方式，//即将变量作为数组的长度，这样做是不被允许的，因为在编译时编译器无法确定数组的长度for (int i = 0; i < n; i++){cin >> p[i].x >> p[i].y >> p[i].type;}for (int j = 0; j < m; j++){cin >> l[j].o1 >> l[j].o2 >> l[j].o3;}char type1=NULL;char type2=NULL;//记得初始化，并且最好写在for循环外面for (int j = 0; j < m; j++){int t1 = 0;int t2 = 0;for (int i = 0; i < n; i++){if (l[j].o1 + l[j].o2 * p[i].x + l[j].o3 * p[i].y > 0){if(t1==0){type1 = p[i].type;}if (p[i].type != type1){cout << "No" << endl;break;}t1++;}if (l[j].o1 + l[j].o2 * p[i].x + l[j].o3 * p[i].y < 0){if (t2 == 0){type2 = p[i].type;}if (p[i].type != type2){cout << "No" << endl;break;}t2++;}}if (t1 + t2 == n){cout << "Yes" << endl;}}return 0;
}
