毁灭

枚举弦心距
求出边界

#include<iostream>#include<cstring>#include<algorithm>#include<cstdio>#include<cmath>#include<queue>#include<vector>#include<climits>#include<string>#include<cstdlib>#include<ctime>#define MOD 1000000007#define LL long longusing namespace std;int n,m,i,x,y,rk,j,l,r,t,f,pic[5005][5005],ans,d;int dis(int xx,int yy){    int re;    re=(xx-x)*(xx-x)+(yy-y)*(yy-y);    return re;}int main(){    scanf("%d%d",&n,&m);    for(i=1;i<=m;i++)    {        scanf("%d%d%d",&x,&y,&rk);        for(j=0;j<=rk;j++)        {            d=sqrt(rk*rk-j*j);            l=max(x-d,1);            r=min(x+d,n);            t=max(y-j,1);            f=min(y+j,n);            pic[l][t]+=1;            pic[r+1][t]-=1;            pic[l][f]+=1;            pic[r+1][f]-=1;         }    }    for(i=1;i<=n;i++)        for(j=1;j<=n;j++)        {            pic[i][j]+=pic[i-1][j];            if(!pic[i][j]) ans++;        }           printf("%d",ans);    return 0;}