POJ-2007

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G++要用%f而C++要用%lf
极角排序

#include <cstdio>#include <cstring>#include <cstdlib>#include <cmath>#include <climits>#include <ctime>#include <iostream>#include <algorithm>#include <vector>#include <stack>#include <queue>#include <string>#include <map>#include <set>#include <utility>using namespace std;struct P{    double x, y;    P() {}    P(double x, double y) : x(x), y(y) {}    P operator +(const P &p)    {        return P(x + p.x, y + p.y);    }    P operator -(const P &p)    {        return P(x - p.x, y - p.y);    }    P operator *(const double &d)    {        return P(x * d, y * d);    }    P operator /(const double &d)    {        return P(x / d, y / d);    }    bool operator ==(const P &p)    {        return x == p.x && y == p.y;    }    P operator =(const P &p)    {        x = p.x, y = p.y;        return *this;    }    double det(const P &p)    {        return x * p.y - y * p.x;    }    double dot(const P &p)    {        return x * p.x + y * p.y;    }};P in_arr[500];bool Graham_cmp(P a, P b){    P origin(0.0, 0.0);    return (a - origin).det(b - origin) > 0;}int main(){//    freopen("in.in", "r", stdin);    int i = 0;    while(scanf("%lf %lf", &in_arr[i].x, &in_arr[i].y) != EOF)    {        i += 1;    }    sort(in_arr + 1, in_arr + i, Graham_cmp);    for(int j = 0; j < i; ++j) printf("(%.0lf,%.0lf)\n", in_arr[j].x, in_arr[j].y);return 0;}

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