50148. Stack Rectangles, Again

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <limits.h>

#define max(a,b) ((a)>(b)?(a):(b))
#define min(a,b) ((a)<(b)?(a):(b))

typedef struct{
    int l;
    int w;
} s_box;

int n;
s_box box[128];

int max_size = 0;
int target_area;

int can_place(s_box* a, s_box* b){
    #ifdef LARGEONSMALL
    if(a->l >= b->l && a->w >= b->w) return 1;
    else if(a->l >= b->w && a->w >= b->l) return 1;
    else return 0;
    #endif
    #ifdef SMALLONLARGE
    if(a->l <= b->l && a->w <= b->w) return 1;
    else if(a->l <= b->w && a->w <= b->l) return 1;
    else return 0;
    #endif
}

int get_area_sum(int arr[], int arr_size){
    int ans = 0;
    for(int i = 0; i < arr_size; i++){
        int idx = arr[i];
        ans += (box[idx].l * box[idx].w);
    }
    return ans;
}

void dfs(int arr[], int arr_size, int now_idx){
    if(now_idx == n){
        if(arr_size < max_size) return;
        int this_area_sum = get_area_sum(arr, arr_size);

        if(arr_size > max_size){
            max_size = arr_size;
            target_area = this_area_sum;
        }
        else{
            #ifdef MAXAREASUM
            target_area = max(target_area, this_area_sum);
            #endif
            #ifdef MINAREASUM
            target_area = min(target_area, this_area_sum);
            #endif
        }
    }
    else{
        // choose (if possible)
        if(arr_size == 0 || can_place(&box[now_idx], &box[arr[arr_size - 1]])){
            arr[arr_size] = now_idx;
            dfs(arr, arr_size + 1, now_idx + 1);
            arr[arr_size] = -1;
        }

        // no choose
        dfs(arr, arr_size, now_idx + 1);
    }
}

int main(){
    scanf("%d", &n);
    for(int i = 0; i < n; i++){
        scanf("%d %d", &box[i].l, &box[i].w);
    }
    #ifdef MAXAREASUM
    target_area = INT_MIN;
    #endif
    #ifdef MINAREASUM
    target_area = INT_MAX;
    #endif

    int arr[128] = {0};
    dfs(arr, 0, 0);

    printf("%d %d\n", max_size, target_area);
}