HII guys this is totally geometry based problem there is nothing to code just use formula
LOGIC::how to find centroid of a polygon u can this concept or formula given below
The centroid of a non-self-intersecting closed polygon defined by n vertices (x0,y0), (x1,y1), ..., (xn−1,yn−1) is the point (Cx, Cy), where
and where A is the polygon's signed area,
.[13]
In these formulas, the vertices are assumed to be numbered in order of their occurrence along the polygon's perimeter, and the vertex ( xn, yn ) is assumed to be the same as (x0, y0 ). Note that if the points are numbered in clockwise order the area A, computed as above, will have a negative sign; but the centroid coordinates will be correct even in this case
IF still u have problem to implement this u can refer my solution given below::::
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44 | #include<bits/stdc++.h>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cassert>
#include <algorithm>
#include <vector>
using namespace std;
int main()
{
int t;
scanf("%d",&t);
while(t--)
{
int n,i;
scanf("%d",&n);
int x[n+1],y[n+1];
double ans1=0,ans2=0;
for(i=0;i<n;i++)
{
scanf("%d %d",&x[i],&y[i]);
}
double A=0,cx=0,cy=0,p;
x[n]=x[0];
y[n]=y[0];
for(i=0;i<=n-1;i++)
{
p=(x[i]*y[i+1])-(x[i+1]*y[i]);
cx+=p*(x[i]+x[i+1]);
cy+=p*(y[i]+y[i+1]);
A+=p;
}
A/=2;
cx/=(6*A);
cy/=(A*6);
if (fabs(cx) < 0.005 - 1e-9) cx = 0;
if (fabs(cy) < 0.005 - 1e-9) cy = 0;
printf("%.2f %.2f\n",
cx + 1e-9 * (cx >= -1e-9 ? 1 : -1),
cy + 1e-9 * (cy >= -1e-9 ? 1 : -1));
}
}
|
