CF 118C Fancy Number

CF 118C

    这个题目可以暴力枚举变成0~9的情况，但究竟优先变哪一个位置需要分情况进行讨论，因此可以先按优先级将位置进行排序，依次改变该位置上的数字即可。

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int number, a[10010], b[11][10010], sum[11], r[10010];
char str[10010];
int cmp(const void *_p, const void *_q)
{
    int *p = (int *)_p;
    int *q = (int *)_q;
    if(abs(a[*p] - number) == abs(a[*q] - number))
    {
        if(a[*p] == a[*q])
        {
            if(number > a[*p])
                return *q - *p;
            else
                return *p - *q;
        }
        else
        {
            if(number < a[*p] && number < a[*q])
                return *p - *q;
            else if(number > a[*p] && number > a[*q])
                return *q - *p;
            else
            {
                if(a[*p] > a[*q])
                    return -1;
                else
                    return 1;
            }
        }
    }
    else
        return abs(a[*p] - number) - abs(a[*q] - number);
}
int main()
{
    int i, j, n, k, flag , cost;
    while(scanf("%d%d", &n, &k) == 2)
    {
        scanf("%s", str);
        for(i = 0; i < n; i ++)
            a[i] = str[i] - '0';
        cost = 1000000000;
        for(i = 0; i < 10; i ++)
        {
            for(j = 0; j < n; j ++)
                r[j] = j;
            number = i;
            qsort(r, n, sizeof(r[0]), cmp);
            sum[i] = 0;
            int ok = 0,num = 0;
            for(j = 0; j < n; j ++)
            {
                if(num == k)
                    ok = 1;
                if(!ok)
                {
                    b[i][r[j]] = i;
                    sum[i] += abs(number - a[r[j]]);
                    num ++;
                }
                else
                    b[i][r[j]] = a[r[j]];
            }
            if(sum[i] < cost)
            {
                cost = sum[i];
                flag = i;
            }
            else if(sum[i] == cost)
            {
                int t = 0;
                for(j = 0; j < n; j ++)
                    if(b[i][j] != b[flag][j])
                    {
                        if(b[i][j] < b[flag][j])
                            t = 1;
                        break;
                    }
                if(t)
                {
                    cost = sum[i];
                    flag = i;
                }
            }
        }
        printf("%d\n", cost);
        for(i = 0; i < n; i ++)
            printf("%d", b[flag][i]);
        printf("\n");
    }
    return 0;
}