离散化就一定比普通暴力慢吗

#include<bits/stdc++.h>
#define re register
using namespace std;
const int N = 1005;
int n,m,num[N][N];
inline int read(){
    int f = 0,x = 0;char ch;
    do{ch = getchar();f |= (ch == '-');}while(!isdigit(ch));
    do{x = (x << 3) + (x << 1) + (ch ^ 48);ch = getchar();}while(isdigit(ch));
    return f ? -x : x;
}
int main(){
    n = read(),m = read();
    for(re int i = 1;i <= m;++i){
        int x = read(),y = read(),x_ = read(),y_ = read();
        //cout << min(x,x_) << ' ' << max(x,x_) << ' ' << min(y,y_) << ' ' << max(y,y_) << endl;
        for(re int j = x;j <= x_;++j){
            for(re int k = y;k <= y_;++k){
                ++num[j][k];
            }
        }
    }
    for(re int i = 1;i <= n;++i){
        for(re int j = 1;j <= n;++j)printf("%d ",num[i][j]);
        putchar('\n');
    }
    return 0;
}

一般的暴力

// luogu-judger-enable-o2
#include<bits/stdc++.h>
#define re register
using namespace std;
const int N = 1005;
int n,m,x[N],y[N],x2[N],y2[N];
inline int read(){
    int f = 0,x = 0;char ch;
    do{ch = getchar();f |= (ch == '-');}while(!isdigit(ch));
    do{x = (x << 3) + (x << 1) + (ch ^ 48);ch = getchar();}while(isdigit(ch));
    return f ? -x : x;
}
int main(){
    n = read(),m = read();
    for(re int i = 1;i <= m;++i){
        int a = read(),b = read(),c = read(),d = read();
        x[i] = a,x2[i] = c,y[i] = b,y2[i] = d;
    }
    //for(re int i = 1;i <= m;++i)cout << x[i] << ' ' << x2[i] << ' ' << y[i] << ' ' << y2[i] << '\n'; 
    for(re int i = 1;i <= n;++i){
        for(re int j = 1;j <= n;++j){
            int cnt = 0;
            for(re int k = 1;k <= m;++k){
                if(i >= x[k] && i <= x2[k] && j >= y[k] && j <= y2[k])++cnt;
            }
            printf("%d ",cnt);
        }
        putchar('\n');
    }
    return 0;
}

离散的代码2AC其他全T了