【点的定位】Save the Students! UVALive

Think:
1知识点：判断一个点是否在三角形内/圆形内/正方形内
2题意：输入多个三角形和圆形和正方形，询问最终有多少个点在输入的三角形内或者圆形内或者正方形内

vjudge题目链接

以下为Accepted代码

#include <cstdio>#include <cstring>#include <algorithm>#include <cmath>using namespace std;struct point{/*记录点的信息*/    double x;    double y;};struct v{/*记录边的信息*/    point star;/*边的起点*/    point en;/*边的终点*/};struct triangle{/*记录三角形信息*/    point A;/*三角形的顶点A*/    point B;/*三角形的顶点B*/    point C;/*三角形的顶点C*/};triangle tre[104];int tr;struct square{    int x;/*正方形左下角的横坐标*/    int y;/*正方形左下角的纵坐标*/    int l;/*正方形的边长*/};square squ[104];int sq;struct circle{    int x;/*圆心的横坐标*/    int y;/*圆心的纵坐标*/    int r;/*圆的半径*/};circle cir[104];int ci;double crossProduct(v * v1, v * v2);/*向量叉积*/bool inTrianle(triangle t, point P);/*判断点是否在三角形内*/bool inSquare(square t, int x, int y);/*判断点是否在正方形内*/bool inCircle(circle t, int x, int y);/*判断点是否在圆内*/int main(){    int T, n, i, j, k, num;    char st[14];    scanf("%d", &T);    while(T--){        tr = sq = ci = 0;        scanf("%d", &n);        while(n--){            scanf("%s", st);            if(st[0] == 'C'){                scanf("%d %d %d", &cir[ci].x, &cir[ci].y, &cir[ci].r);                ci++;            }            else if(st[0] == 'S'){                scanf("%d %d %d", &squ[sq].x, &squ[sq].y, &squ[sq].l);                sq++;            }            else {                scanf("%lf %lf %lf %lf %lf %lf", &tre[tr].A.x, &tre[tr].A.y, &tre[tr].B.x, &tre[tr].B.y, &tre[tr].C.x, &tre[tr].C.y);                tr++;            }        }        num = 0;        for(i = -200; i <= 200; i++){            for(j = -200; j <= 200; j++){                bool flag = false;                for(k = 0; k < ci; k++){                    if(inCircle(cir[k], i, j)){                        flag = true;                        break;                    }                }                if(!flag){                    for(k = 0; k < sq; k++){                        if(inSquare(squ[k], i, j)){                            flag = true;                            break;                        }                    }                }                if(!flag){                    point t;                    for(k = 0; k < tr; k++){                        t.x = (double)i, t.y = (double)j;                        if(inTrianle(tre[k], t)){                            flag = true;                            break;                        }                    }                }                if(flag)                    num++;            }        }        printf("%d\n", num);    }    return 0;}double crossProduct(v * v1, v * v2){    v vt1, vt2;    double result = 0;    vt1.star.x = 0;    vt1.star.y = 0;    vt1.en.x = v1->en.x - v1->star.x;    vt1.en.y = v1->en.y - v1->star.y;    vt2.star.x = 0;    vt2.star.y = 0;    vt2.en.x = v2->en.x - v2->star.x;    vt2.en.y = v2->en.y - v2->star.y;    result = vt1.en.x * vt2.en.y - vt2.en.x * vt1.en.y;    return result;}bool inTrianle(triangle t, point p){    v AB, AC, BC, PA, PB, PC;    AB.star = t.A;    AB.en = t.B;    AC.star = t.A;    AC.en = t.C;    BC.star = t.B;    BC.en = t.C;    PA.star = p;    PA.en = t.A;    PB.star = p;    PB.en = t.B;    PC.star = p;    PC.en = t.C;    double Sabc = fabs(crossProduct(&AB, &AC));    double Spab = fabs(crossProduct(&PA, &PB));    double Spac = fabs(crossProduct(&PA, &PC));    double Spbc = fabs(crossProduct(&PB, &PC));    if(Sabc == Spab + Spac + Spbc)        return true;    else        return false;}bool inSquare(square t, int x, int y){    if(x >= t.x && x <= t.x+t.l && y >= t.y && y <= t.y+t.l)        return true;    else        return false;}bool inCircle(circle t, int x, int y){    int ans = (x-t.x)*(x-t.x) + (y-t.y)*(y-t.y);    if(ans <= t.r*t.r)        return true;    else        return false;}