50215. Set Cover

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

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

typedef struct{
    uint32_t num;
    int cost;
} s_set;

int n;
uint32_t all;
s_set set[25];

void get_info(s_set* st, char* s){
    st->num = 0;
    st->cost = 0;
    for(int i = 0; s[i] != '\0'; i++){
        st->num |= ((uint32_t)1 << (s[i] - 'a'));
        st->cost += (s[i] - 'a' + 1);
    }
}

void dfs(uint32_t now_set, int now_idx, int now_cost, int *min_cost){
    if(now_cost >= (*min_cost)) return;
    if(now_set == all){
        (*min_cost) = min((*min_cost), now_cost);
        return;
    }
    else if(now_idx == n) return;
    else{
        // no choose
        dfs(now_set, now_idx + 1, now_cost, min_cost);
        // choose
        dfs(now_set | set[now_idx].num, now_idx + 1, now_cost + set[now_idx].cost, min_cost);
    }
}

signed main(){
    for(int i = 0; i < 26; i++) all |= ((uint32_t)1 << (i));

    char dummy[55];
    while(scanf("%d", &n) != EOF){
        for(int i = 0; i < n; i++){
            scanf("%s", dummy);
            get_info(&set[i], dummy);
        }
        int min_cost = INT_MAX;
        dfs((uint32_t)0, 0, 0, &min_cost);
        printf("%d\n", min_cost);
    }
}