为什么这两个程序运行所需时间差别如此之大

#include <iostream>
#include <cmath>
using namespace std;
typedef struct
{
    int x,y,r;
}rad_;
int exchange(int *a,int *b)
{
    int c;
    c=*b;
    *b=*a;
    *a=c;
    return 0;
}
int main()
{
    int x1,x2,y1,y2,i,j,n,sum=0;
    rad_ *rads;
    cin>>x1>>y1>>x2>>y2>>n;
    if(x1>x2)
        exchange(&x1,&x2);
    if(y1>y2)
        exchange(&y1,&y2);
    rads=new rad_[n];
    for(i=0;i<n;++i)
        cin>>rads[i].x>>rads[i].y>>rads[i].r;
    for(i=y1;i<=y2;++i)//检测纵向
    {
        for(j=0;j<n;++j)
            if(rads[j].r-sqrt((x1-rads[j].x)*(x1-rads[j].x)+(i-rads[j].y)*(i-rads[j].y))>=-1e-6)
                break;
        if(j==n)
            ++sum;
        for(j=0;j<n;++j)
            if(rads[j].r-sqrt((x2-rads[j].x)*(x2-rads[j].x)+(i-rads[j].y)*(i-rads[j].y))>=-1e-6)
                break;
        if(j==n)
            ++sum;
    }
    for(i=x1+1;i<x2;++i)//检测横向
    {
        for(j=0;j<n;++j)
            if(rads[j].r-sqrt((i-rads[j].x)*(i-rads[j].x)+(y1-rads[j].y)*(y1-rads[j].y))>=-1e-6)
                break;
        if(j==n)
            ++sum;
        for(j=0;j<n;++j)
            if(rads[j].r-sqrt((i-rads[j].x)*(i-rads[j].x)+(y2-rads[j].y)*(y2-rads[j].y))>=-1e-6)
                break;
        if(j==n)
            ++sum;
    }
    cout<<sum;
    return 0;
}

#include <iostream>
    #include <vector>
    #include <cstdio>
    #include <cstring>
    #include <algorithm>
    #include <set>
    #include <map>
    #include <queue>
    #include <stack>
    #include <string>
    #include <sstream>
    #include <ctime>
    #include <cmath>

    using namespace std;

    #define REP(i,n) for((i)=0;(i)<(int)(n);(i)++)
    #define FE(v,itr) for(__typeof((v).begin()) itr=(v).begin();itr!=(v).end();itr++)
    #define SZ(x) ((int) (x).size())
    #define RA(x) (x).begin(), (x).end()
    #define CLEAR(a, b) memset(a, b, sizeof(a))
    #define PB push_back
    #define MP make_pair
    #define INF 2000000000

    typedef long long ll;
    typedef vector<int> vi;
    typedef vector<string> vs;
    typedef pair<int,int> pii;

    int x1,x2,y3,y2,n;
    int x[1005],y[1005],r[1005];


    int main() {

        int w,ww,www,wwww;
        cin>>w>>ww>>www>>wwww;
        x1 = min(w,www); x2 = max(w,www); y3 =min(ww,wwww); y2 = max(ww,wwww);
        cin>>n; int i,j,k;
        REP(i,n) {
            cin>>x[i]>>y[i]>>r[i];
        }
        int ans=0;
        for(i=x1;i<=x2;i++) {
            int warm = 0;
            REP(j,n) {
                if ((x[j]-i)*(x[j]-i) + (y[j]-y3)*(y[j]-y3) <= r[j]*r[j]) {
                    warm = 1; break;
                }
            }
            if (!warm) ans++;
        }

        for(i=x1;i<=x2;i++) {
            int warm = 0;
            REP(j,n) {
                if ((x[j]-i)*(x[j]-i) + (y[j]-y2)*(y[j]-y2) <= r[j]*r[j]) {
                    warm = 1; break;
                }
            }
            if (!warm) ans++;
        }

        for(i=y3+1;i<y2;i++) {
            int warm = 0;
            REP(j,n) {
                if ((x[j]-x1)*(x[j]-x1) + (y[j]-i)*(y[j]-i) <= r[j]*r[j]) {
                    warm = 1; break;
                }
            }
            if (!warm) ans++;
        }

        for(i=y3+1;i<y2;i++) {
            int warm = 0;
            REP(j,n) {
                if ((x[j]-x2)*(x[j]-x2) + (y[j]-i)*(y[j]-i) <= r[j]*r[j]) {
                    warm = 1; break;
                }
            }
            if (!warm) ans++;
        }

        cout << ans << endl;


        cin.get();
        cin.get();
        return 0;
    }