题解 | 支付宝消费打折

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef long long ll;

int compare(const void*a, const void*b){
    ll ca = *(ll*)a;
    ll cb = *(ll*)b;
    if(ca < cb)
        return -1;
    if(ca > cb)
        return 1;
    
    return 0;
}

int main(void) {
    ll n, k;   //n个物品和有的钱
    scanf("%lld%lld", &n, &k);

    ll* p = (ll*)malloc(n * sizeof(ll));
    for(int i = 0; i < n; i++)
        scanf("%lld", &p[i]);
    
    char ch[100005];
    scanf("%s", ch);
    for(int i = 0; i < n; i++){
        if(ch[i] == '1')
            p[i] *= 95;
        else
            p[i] *= 100;
    }

    qsort(p, n, sizeof(long long), compare);

    int ans = 0;
    k *= 100;
    if(k >= p[0]){
        for(int i = 0; i < n; i++){
            k = k - p[i];
            if(k >= 0)
                ans++;
            else
                break;
        }
    }
    printf("%d", ans);

    free(p);
    return 0;
}