poj 1113 graham模板（水平序）

這題不多說，裸的模板，graham掃瞄演算法，通過棧比較當前point與棧頂的兩個point是否滿足左轉的關係，不滿足時退棧直到棧空或這滿足時。上**：

/*

memory: 180 kb        time: 16 ms
language: c++        result: accepted
by coolwind
*/#include 
#include 
#include 
#include 
using
namespace
std;
#define  maxn 2000
const
double pi = acos(-1.0
);struct
point
}point[maxn];
intcmpxy(point a, point b)
intxmul(point a, point b, point o)
double
dis(point a, point b)
point stack[maxn];
inttop;
double graham(int n, int
l)    
int len =top;
stack[++top] = point[n - 1
];    
for(i = n - 2; i >= 0; i --)
double res = 0
;    
for(i = 0; i < top; i ++)
res += dis(stack[i],stack[i + 1
]);    res += l * 2.0 *pi;
return
res;
}int
main()
return0;
}

poj 1113 凸包模板

include include include include include include using namespace std define n 1050 define pi acos 1.0 int n,r struct point point operator point b const...

POJ 1113 Wall 凸包 模板題

用不嚴謹的話來講，給定二維平面上的點集，凸包就是將最外層的點連線起來構成的凸多邊型，它能包含點集中所有的點。題意 給出n個點 n 1e3和長度l,求出包圍n個點的最小凸多邊形周長 多邊形距離這n個點的距離 l?若不考慮l 則答案為凸包的周長,考慮條件l,由如下圖形 答案為 凸包周長 以l為半徑的圓的...

計算幾何 poj1113 Wall

進行凸包掃瞄並求面積即可。include include include includeusing namespace std struct point int cmp const void elem1 const void elem2 void add point a,int k double d...