HNU 12812 Broken Audio Signal

题目链接：http://acm.hnu.cn/online/?action=problem&type=show&id=12812

一直弄错了一个题意，教训啊，比赛最怕的就是弄错题意了

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<cstdlib>
using namespace std;
const int maxn = 1000+5;
int num[maxn],X[maxn],flag[maxn];

int main()
{
//    freopen("A2.out","w",stdout);
//    freopen("A.in","r",stdin);
    int n;
    char str[30];
    while(scanf("%d",&n),n)
    {
        memset(flag,0,sizeof(flag));
        int num_x = 0,end = 0;
        for(int i = 1;i <= n;++i)
        {
            scanf("%s",str);
            if(str[0] == 'X' || str[0] == 'x')
            {
                flag[i] = 1;
                X[num_x++] = i;
            }
            else num[i] = atoi(str);
            if(i > 1 && flag[i] == 1 && flag[i-1] == 1)
            end = 1;
        }
        if(num_x >= n || end)   /////全是x无法判断,超过两个x在一起也是无解
        {
            printf("none
");
            continue;
        }
        for(int i = 1;i < n;++i)
        if(flag[i] == 0 && flag[i+1] == 0)
        {
            if(((i & 1) && num[i] >= num[i+1]) || (!(i & 1) && num[i] <= num[i+1]))
            {
                end = 1;
                break;
            }
        }
        if(end)        /////出现不符合规则的情况
        {
            printf("none
");
            continue;
        }
        int l = -0x7fffffff,r = 0x7fffffff;
        for(int i = 0;i < num_x;++i)
        if(X[i] & 1)
        {
            if(X[i] > 1 && flag[X[i]-1] == 0)
            r = min(r,num[X[i]-1] - 1);
            if(X[i] < n && flag[X[i]-1] == 0)
            r = min(r,num[X[i]+1] - 1);
        }
        else
        {
            if(X[i] > 1 && flag[X[i]-1] == 0)
            l = max(l,num[X[i]-1] + 1);
            if(X[i] < n && flag[X[i]+1] == 0)
            l = max(l,num[X[i]+1] + 1);
        }
        if(l == r)
        printf("%d
",l);
        else if(l > r)
        printf("none
");
        else printf("ambiguous
");
    }
    return 0;
}