【Bit String Reordering UVALive - 6832 】【模拟】

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
using namespace std;
void Swap(int& a, int &b)
{
    int t = b;
    b = a;
    a = t;
}
int getSum(int a[], int len)
{
    int sum = 0;
    for(int i = 0; i < len; i++)
        sum += a[i];
    return sum;
}
const int maxn = 20, INF = 0x3f3f3f3f;
int N, M;
int b[maxn], p, bb[maxn];
int cal()
{
    if(getSum(b, N) != getSum(bb, N))       //若连和都不同，再交换相邻元素又有何用
        return INF;
    int cnt = 0, temp[maxn];
    memcpy(temp, b, sizeof(b));         //这里要注意，将你要变换的串存储在一个临时的串中，这样在得到交换次数的同时又不会改变原串
    for(int i = 0; i < N; i++)
    {
        if(bb[i] == temp[i]) continue;
        for(int j = i + 1; j < N; j++)
        {
            if(bb[i] == temp[j])        //找到相等的后，依次交换相邻的元素，直到它到达指定位置
            {
                while(i < j)
                {
                    Swap(temp[j-1], temp[j]);
                    --j;
                    cnt++;
                }
                break;
            }
        }
    }
    return cnt;
}
int main()
{
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
    while(scanf("%d%d", &N, &M)  != EOF)
    {
        memset(b, 0, sizeof(b));
        for(int i = 0; i < N; i++)
            scanf("%d", &b[i]);
        int idx = 0, value = 1;
        while(M--)
        {
            scanf("%d", &p);
            while(p--)
                bb[idx++] = value;
            value ^= 1;     //这里用异或的原因是利用它不进位的加法的特性
        }
        int minn = INF;
        minn = min(minn, cal());
        for(int i = 0; i < N; i++)
            bb[i] ^= 1;     //在看另一种符合要求的01串
        minn = min(minn, cal());
        printf("%d\n", minn);
    }
}